Chemistry 3720 Old Exams

Practice Exams & Keys 2015-17 Spring 2017

Page File 3 Spring 2017 Exam 1 10 Spring 2017 Exam 1 Key 16 Spring 2017 Exam 2 23 Spring 2017 Exam 2 Key 29 Spring 2017 Exam 3 36 Spring 2017 Exam 3 Key 42 Spring 2017 Final (No Key)

Chemistry 3720, Spring 2017 Exam 1 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

1. (8 pts) Give a retrosynthetic plan for building the following molecule from the sources of carbon shown. Then show your synthesis in the forward direction that would result in the alkyl bromide. You may assume that you have access to all of the usual reagents in an organic lab.

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

2 3. (8 pts) The mass spectrum below belongs to one of the five compounds shown. Indicate which molecule matches the spectrum and explain why you chose that one and not the other four. Atomic masses (in atomic mass units, a.m.u.) are as follows: C = 12 ; H = 1 ; O = 16 ; F = 19 ; Cl = 35.45 ; Br = 79.90.

4. (8 pts) Draw a complete mechanism for the following ester to ether conversion.

3 5. (9 pts) For each of the following reactions, label the oxidation state of the highlighted carbon atoms in the starting material and product. Then indicate whether the reaction is an oxidation, reduction or neither, and give a reagent (above the arrow) that will accomplish the conversion.

6. (7 pts) IR spectrum A belongs to a starting material and B belongs to the product when A is reacted under certain conditions. Of the reactions shown, which one matches the IR data give? Explain your choice.

4 7. (16 pts) In the boxes below, give the major product(s) from each step of the following sequence. The given clues might help you to work out the answers. If no reaction is expected, write “NR” in the box.

8. (8 pts) For each of the following epoxide ring-opening reactions, explain in some detail the regioselectivity and stereoselectivity observed. Discuss the different mechanisms operating.

5 9. (8 pts) The following attempted synthesis contains a fatal flaw that prevents it from actually working. What is wrong here and how would you make it work? Show the steps and reagents required for your synthesis.

10. (8 pts) For each of the following molecules, indicate how many different signals you expect to see in the proton (1H) NMR spectrum. Then label the approximate chemical shift (ppm) for the highlighted atoms.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (parts per million)

R3C-H (alkyl) 0.9 to 1.8 R3N-C-H (N neighbor) 2.2 to 2.9 C=C-C-H (allylic) 1.6 to 2.6 Cl-C-H (Cl neighbor) 3.1 to 4.1 O=C-C-H (alpha to C=O) 2.1 to 2.5 Br-C-H (Br neighbor) 2.7 to 4.1 NC-C-H (alpha to CN) 2.1 to 3.0 -O-C-H (O neighbor) 3.3 to 3.7

C C H (alkyne) 2.5 R2N-H (amine) 1 to 3 Ar-C-H (benzylic) 2.3 to 2.8 RO-H (alcohol) 0.5 to 5 C=C-H (alkene) 4.5 to 6.5 Ar-O-H (phenol) 6 to 8

Ar-H (benzene) 6.5 to 8.5 -CO2H (carboxylic acid) 10 to 13 O=C-H (aldehyde) 9 to 10

Approximate 13C NMR Chemical Shifts (parts per million)

RCH3 (alkyl) 0 to 35 RCH2Br (alkyl bromide) 20 to 40

R2CH2 (alkyl) 15 to 40 RCH2Cl (alkyl chloride) 25 to 50

R3CH (alkyl) 25 to 50 RCH2NH2 (alkyl amine) 35 to 50

R4C (alkyl) 30 to 40 RCH2OR (alcohol or ether) 50 to 65 R-CC-R (alkyne) 65 to 90 RCN (nitrile) 110 to 125

R2C=CR2 (alkene) 100 to 150 RCO2R (acid, ester) 160 to 185

Benzene C (aromatic) 110 to 175 RCHO, R2CO (ald’hyde, ketone) 190 to 220

Approximate IR Absorption Frequencies (cm-1) Stretching Vibrations -O-H (alcohol) 3200 to 3600 C=C (alkenes) 1620 to 1680 -O-H (carbox. acid) 2500 to 3600 C=O (ald., ketones) 1710 to 1750

R2N-H (amine) 3350 to 3500 C=O (acyl halides) 1770 to 1815 sp C-H (alkynes) 3310 to 3320 C=O (esters) 1730 to 1750 sp2 C-H (alkenes) 3000 to 3100 C=O (amides) 1680 to 1700 sp3 C-H (alkanes) 2850 to 2950 sp2 C-O (carbonyls) 1200 triple bond (alkynes) 2100 to 2200 sp3 C-O (alcoh., ethers) 1025 to 1200 triple bond (nitriles) 2240 to 2280 Bending Vibrations

RCH=CH2 (alkenes) 910, 990 Monosubstit’d benzene 730 to 770, 690 to 710

R2C=CH2 (alkenes) 890 ortho-disubstit’d benzene 735 to 770

R2C=CHR’ (alkenes) 790 to 840 meta-disubstit’d benzene 750 to 810, 680 to 730 para-disubstituted benzene 790 to 840 Chemistry 3720, Spring 2017 Exam 1 – Key Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

4. (8 pts) Draw a complete mechanism for the following ester to ether conversion.

8. (8 pts) For each of the following epoxide ring-opening reactions, explain in some detail the regioselectivity and stereoselectivity observed. Discuss the different mechanisms operating.

6 Chemistry 3720, Spring 2017 Exam 2 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

#Pi bonds and/or Cycles = [#C - (#H/2) - (#X/2) + #N/2] +1

1. (8 pts) Provide the major product(s) expected to be formed under the following conditions and then draw a detailed mechanism for the process that includes all important resonance structures where applicable. Why is there only one major product formed here?

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any regiochemical issues where applicable.

2 3. (9 pts) For each of the following molecules, draw a Frost circle and populate the molecular orbitals with the appropriate number of electrons. Then apply Hückel’s rule to each system and indicate which molecule(s) is/are aromatic. Give a few words of explanation for your choices.

4. (8 pts) Draw the major final product expected from each of the following reactions:

3 5. (18 pts) A new anti-cancer compound has been isolated from a microorganism and is found, from the mass + spectrum, to have the formula C12H14O2 and M of 190 atomic mass units. The infra-red spectrum has signals at 3500, 1740, 740 and 700 wavenumbers and the proton and carbon spectra are given below. Provide the structure of the unknown and then indicate which signals belong to which atoms in the 1H NMR spectrum.

1H NMR (ppm): 0.86 (d, 6H, J = 7.0 Hz); 2.38 (octet, 1H, J = 7.0 Hz); 5.63 (dd, 1H, J = 12.0, 7.0 Hz); 6.35 (d, 1H, J = 12.0 Hz); 7.55 (d, 2H, J = 8.0 Hz); 7.83 (d, 2H, J = 8.0 Hz); 12.71 (s, 1H).

13C NMR (ppm): 22.6 (q); 28.0 (d); 127.7 (d); 129.0 (d); 129.4 (s); 130.2 (d); 141.6 (s); 142.4 (d); 169.3 (s).

4 6. (8 pts) Provide the major product that you expected to be formed under the following conditions. Then draw a complete mechanism, including all important resonance structures, for the product’s formation. Explain, briefly, why this particular product is major.

7. (7 pts) The 13C spectrum below belongs to one of the five molecules given. Indicate which one you think matches the NMR data and explain your choice by pointing out which signal matches which carbon(s) and how the coupling data helped inform your decision.

13C NMR (ppm): 23.3 (q); 33.2 (d); 126.6 (d); 129.6 (d); 134.1 (s); 154.2 (s); 191.0 (d).

5 8. (6 pts) Provide the major product that you would expect to be formed under each of the following reaction conditions. Then explain the outcomes by discussing the effect of temperature on the reaction pathway.

9. (16 pts) In the boxes provided, draw the expected major product from each step in the following synthetic scheme. Use the clues as needed and be careful if/when stereochemistry/regiochemistry is an issue.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (parts per million)

C C H (alkyne) 2.5 R2N-H (amine) 1 to 3 Ar-C-H (benzylic) 2.3 to 2.8 RO-H (alcohol) 0.5 to 5 C=C-H (alkene) 4.5 to 6.5 Ar-O-H (phenol) 6 to 8

Ar-H (benzene) 6.5 to 8.5 -CO2H (carboxylic acid) 10 to 13 O=C-H (aldehyde) 9 to 10

Approximate 13C NMR Chemical Shifts (parts per million)

RCH3 (alkyl) 0 to 35 RCH2Br (alkyl bromide) 20 to 40

R2CH2 (alkyl) 15 to 40 RCH2Cl (alkyl chloride) 25 to 50

R3CH (alkyl) 25 to 50 RCH2NH2 (alkyl amine) 35 to 50

R4C (alkyl) 30 to 40 RCH2OR (alcohol or ether) 50 to 65 R-CC-R (alkyne) 65 to 90 RCN (nitrile) 110 to 125

R2C=CR2 (alkene) 100 to 150 RCO2R (acid, ester) 160 to 185

Benzene C (aromatic) 110 to 175 RCHO, R2CO (ald’hyde, ketone) 190 to 220

Approximate IR Absorption Frequencies (cm-1) Stretching Vibrations -O-H (alcohol) 3200 to 3600 C=C (alkenes) 1620 to 1680 -O-H (carbox. acid) 2500 to 3600 C=O (ald., ketones) 1710 to 1750

RCH=CH2 (alkenes) 910, 990 Monosubstit’d benzene 730 to 770, 690 to 710

R2C=CH2 (alkenes) 890 ortho-disubstit’d benzene 735 to 770

R2C=CHR’ (alkenes) 790 to 840 meta-disubstit’d benzene 750 to 810, 680 to 730 para-disubstituted benzene 790 to 840 Chemistry 3720, Spring 2017 Exam 2 - Key Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

#Pi bonds and/or Cycles = [#C - (#H/2) - (#X/2) + #N/2] +1

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any regiochemical issues where applicable.

4. (8 pts) Draw the major final product expected from each of the following reactions:

1H NMR (ppm): 0.86 (d, 6H, J = 7.0 Hz); 2.38 (octet, 1H, J = 7.0 Hz); 5.63 (dd, 1H, J = 12.0, 7.0 Hz); 6.35 (d, 1H, J = 12.0 Hz); 7.55 (d, 2H, J = 8.0 Hz); 7.83 (d, 2H, J = 8.0 Hz); 12.71 (s, 1H).

13C NMR (ppm): 22.6 (q); 28.0 (d); 127.7 (d); 129.0 (d); 129.4 (s); 130.2 (d); 141.6 (s); 142.4 (d); 169.3 (s).

13C NMR (ppm): 23.3 (q); 33.2 (d); 126.6 (d); 129.6 (d); 134.1 (s); 154.2 (s); 191.0 (d).

6 Chemistry 3720, Spring 2017 Exam 3 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (8 pts) Give a detailed mechanism for each step in the following conversion of a ketone to a dithioacetal that includes any important resonance structures for intermediates that are formed. Label each step in terms of what kind of event is happening (proton transfer, nucleophilic attack, etc.).

1 2. (10 pts) Draw a detailed reaction mechanism for the following nitrile hydrolysis that includes resonance structures for the intermediates that are formed. Label each step in terms of what kind of event is occurring (proton transfer, nucleophilic attack, etc.).

3. (8 pts) Draw a complete reaction mechanism for the following ester saponification process. Label each step in terms of what kind of event is happening (proton transfer, nucleophilic attack, etc.).

2 4. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be careful if any stereochemical and/or regiochemical issues arise.

3 5. (8 pts) Give the expected major and minor products from the following reaction sequence as well as a detailed mechanism, which includes all resonance structures for intermediate(s) for the formation of both major and minor isomers. Explain briefly the regiochemical distribution of products.

6. (8 pts) Provide a complete mechanism for the following Baeyer-Villager ketone oxidation and then explain the regiochemical outcome. What evidence is given in the product structure to help you decide whether the migration process is step-wise or concerted?

4 7. (16 pts) In the boxes below, provide the major product(s) from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

8. (8 pts) Make the following molecule from the compounds given on the right. You have access to all of the usual reagents found in an organic lab and you do not need to show retrosynthesis unless it helps.

5 9. (7 pts) Draw a complete mechanism for the following crossed-aldol synthesis that describes how the final product is formed. Also include any important resonance structures for intermediates that are formed.

10. (7 pts) Provide a complete step-by-step mechanism for the following acetal hydrolysis that includes any important resonance structures for intermediates that are formed. Label what is happening in each step.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (parts per million)

C C H (alkyne) 2.5 R2N-H (amine) 1 to 3 Ar-C-H (benzylic) 2.3 to 2.8 RO-H (alcohol) 0.5 to 5 C=C-H (alkene) 4.5 to 6.5 Ar-O-H (phenol) 6 to 8

Ar-H (benzene) 6.5 to 8.5 -CO2H (carboxylic acid) 10 to 13 O=C-H (aldehyde) 9 to 10

Approximate 13C NMR Chemical Shifts (parts per million)

RCH3 (alkyl) 0 to 35 RCH2Br (alkyl bromide) 20 to 40

R2CH2 (alkyl) 15 to 40 RCH2Cl (alkyl chloride) 25 to 50

R3CH (alkyl) 25 to 50 RCH2NH2 (alkyl amine) 35 to 50

R4C (alkyl) 30 to 40 RCH2OR (alcohol or ether) 50 to 65 R-CC-R (alkyne) 65 to 90 RCN (nitrile) 110 to 125

R2C=CR2 (alkene) 100 to 150 RCO2R (acid, ester) 160 to 185

Benzene C (aromatic) 110 to 175 RCHO, R2CO (ald’hyde, ketone) 190 to 220

Approximate IR Absorption Frequencies (cm-1) Stretching Vibrations -O-H (alcohol) 3200 to 3600 C=C (alkenes) 1620 to 1680 -O-H (carbox. acid) 2500 to 3600 C=O (ald., ketones) 1710 to 1750

RCH=CH2 (alkenes) 910, 990 Monosubstit’d benzene 730 to 770, 690 to 710

R2C=CH2 (alkenes) 890 ortho-disubstit’d benzene 735 to 770

R2C=CHR’ (alkenes) 790 to 840 meta-disubstit’d benzene 750 to 810, 680 to 730 para-disubstituted benzene 790 to 840 Chemistry 3720, Spring 2017 Exam 3 - Key Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

3. (8 pts) Draw a complete reaction mechanism for the following ester saponification process. Label each step in terms of what kind of event is happening (proton transfer, nucleophilic attack, etc.).

2 4. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be careful if any stereochemical and/or regiochemical issues arise.

4 7. (16 pts) In the boxes below, provide the major product(s) from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

6 Chemistry 3720, Spring 2017 Final Exam Student Name:

“Y” Number:

This exam is worth 200 points out of a total of 700 points for Chemistry 3720/3720L. You have 120 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (9 pts) For the following Michael addition, give a complete mechanism, including resonance structures, for the conversion of the enamine into the final product. Explain the observed regioselectivity.

1 2. (9 pts) Provide a detailed mechanism for the following tropane alkaloid synthesis that includes resonance structures for any intermediates that are formed. Label what type of event is happening in each step.

3. (9 pts) Draw a complete mechanism for the following ether synthesis that includes all important resonance structures for intermediates that are formed.

2 4. (9 pts) Provide a detailed mechanism for the following Gabriel amine synthesis that includes important resonance structures for intermediates that are formed.

5. (8 pts) Give a mechanistic interpretation (push arrows) to show how the enantiomerically pure epoxide is converted to the racemic mxture of products. Include resonance structures for any intermediates formed.

3 6. (20 pts) Provide the expected major products from each step of the following synthetic sequences. Be sure to take any stereochemical and regiochemical changes into consideration where applicable.

4 7. (14 pts) In the boxes below, provide the major product from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

8. (8 pts) Provide a retrosynthesis for the following molecule that goes back to the given starting materials. Then, using any of the reactions and reagents encountered in Chemistry 3719/3720, build the molecule.

5 9. (14 pts) For the following multi-step biodegradation of amino acids, insert each of the curved arrows needed to describe each bond-making and bond-breaking process. Also label what is happening in each step (proton transfer, nucleophilic attack, etc.). Note: “Enz” = the enzyme that mediates the process.

6 10. (12 pts) Provide the major product from each step of the following reaction sequence. Be careful when regiochemistry is an issue.

11. (10 pts) When attempted, the synthesis below fails to give the indicated product. Explain what the problem is here and then provide a route that will be successful. Include structures of intermediate products.

7 12. (16 pts) A newly isolated organic compound has the molecular formula C13H16O2; the mass spectrum shows M+ = 204.12 a.m.u., the IR spectrum shows significant signals at 1740, 1200, and 810 cm-1, and the 1H and 13C NMR spectra are given below. Suggest a structure for the unknown molecule that matches the data and then indicate which signals belong to which protons in the 1H NMR spectrum.

1 H NMR (CDCl3) ppm : 1.01 (t, 3H, J = 7.0 Hz); 1.73 (sextet, 2H, J = 7.0 Hz); 2.41 (s, 3H); 4.12 (t, 2H, J = 7.0 Hz); 6.31 (d, 1H, J = 16.0 Hz); 7.39 (d, 1H, J = 8.0 Hz); 7.48 (d, 1H, J = 16.0 Hz); 7.59 (d, 1H, J = 8.0 Hz)

13 C NMR (CDCl3) ppm : 10.3 (q); 21.3 (q); 22.0 (t); 67.5 (t); 116.2 (d); 128.5 (d, double intensity); 128.9 (d, double intensity); 132.2 (s); 137.6 (s); 145.1 (d); 166.5 (s)

8 13. (12 pts) Provide a detailed reaction mechanism for the following process that includes all resonance structures for any intermediates that are formed.

14. (12 pts) Draw a detailed mechanism for the following reaction sequence that includes resonance structures for intermediates. Label what is happening in each step (proton transfer, nucleophilic attack, etc.).

9 15. (9 pts) Provide a detailed mechanism for the following iodoform reaction that explains the formation of the two products. Make sure to include resonance structures for intermediates.

16. (10 pts) From the molecules shown below, choose the one that one matches the given mass spectrum. Then explain your choice and draw the structure of the fragment that corresponds to the base peak. Atomic masses (in a.m.u.) are as follows: C = 12 ; H = 1 ; O = 16 ; F = 19 ; Cl = 35.45 ; Br = 79.90.

10 17. (10 pts) The following reaction results in two products that are formed in equal amounts. Give those products as well as a detailed mechanism that describes how they are formed.

18. (9 pts) For each of the following polymers, circle the repeating unit and give starting materials that could be used to synthesize the material. Indicate if each polymer is formed by addition or condensation.

11 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (parts per million)

C C H (alkyne) 2.5 R2N-H (amine) 1 to 3 Ar-C-H (benzylic) 2.3 to 2.8 RO-H (alcohol) 0.5 to 5 C=C-H (alkene) 4.5 to 6.5 Ar-O-H (phenol) 6 to 8

Ar-H (benzene) 6.5 to 8.5 -CO2H (carboxylic acid) 10 to 13 O=C-H (aldehyde) 9 to 10

Approximate 13C NMR Chemical Shifts (parts per million)

RCH3 (alkyl) 0 to 35 RCH2Br (alkyl bromide) 20 to 40

R2CH2 (alkyl) 15 to 40 RCH2Cl (alkyl chloride) 25 to 50

R3CH (alkyl) 25 to 50 RCH2NH2 (alkyl amine) 35 to 50

R4C (alkyl) 30 to 40 RCH2OR (alcohol or ether) 50 to 65 R-CC-R (alkyne) 65 to 90 RCN (nitrile) 110 to 125

R2C=CR2 (alkene) 100 to 150 RCO2R (acid, ester) 160 to 185

Benzene C (aromatic) 110 to 175 RCHO, R2CO (ald’hyde, ketone) 190 to 220

Approximate IR Absorption Frequencies (cm-1) Stretching Vibrations -O-H (alcohol) 3200 to 3600 C=C (alkenes) 1620 to 1680 -O-H (carbox. acid) 2500 to 3600 C=O (ald., ketones) 1710 to 1750

RCH=CH2 (alkenes) 910, 990 Monosubstit’d benzene 730 to 770, 690 to 710

R2C=CH2 (alkenes) 890 ortho-disubstit’d benzene 735 to 770

R2C=CHR’ (alkenes) 790 to 840 meta-disubstit’d benzene 750 to 810, 680 to 730 para-disubstituted benzene 790 to 840 Spring 2016

Page File 55 Spring 2016 Exam 1 62 Spring 2016 Exam 1 Key 68 Spring 2016 Exam 2 74 Spring 2016 Exam 2 Key 81 Spring 2016 Exam 3 88 Spring 2016 Exam 3 Key 94 Spring 2016 Final (No Key)

Chemistry 3720, Spring 2016 Exam 1 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

1. (8 pts) Give the major products from each step of the reaction sequences below and then show whether the highlighted carbon atoms have been oxidized, reduced or unchanged in each step by assigning each an oxidation number.

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

2 3. (9 pts) The following ketone synthesis is impossible to complete under the given conditions. Explain why and give reagents that would allow for access to the ketone. Include structures of intermediate products.

4. (8 pts) Draw a complete mechanism for the following ester to ether conversion.

3 5. (7 pts) The mass spectrum below belongs to one of the four compounds shown. Indicate which molecule the spectrum belongs to and explain why you chose that one and not the other three. Atomic masses (in atomic mass units, a.m.u.) are as follows: C = 12 ; H = 1 ; O = 16 ; F = 19 ; Cl = 35.45 ; Br = 79.90.

6. (7 pts) Which of the following molecules matches this IR spectrum? Point out important signals that helped you to decide on your choice and why the spectrum does not match the other possibilities.

4 7. (16 pts) In the boxes below, give the major product(s) from each step of the following sequence. The given spectroscopic and molecular formula clues might help you to work out the answers.

8. (9 pts) Draw the structures of each of the following molecules and then provide the reagents needed to convert each of the given starting materials into the required product.

5 9. (8 pts) Within each of the following pairs of molecules circle the one required for the answer and give a few words of explanation for your choice.

10. (8 pts) Provide a suitable organic compound that would serve as a precursor (starting material) for each of the following molecules under the given conditions.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (parts per million)

C C H (alkyne) 2.5 R2N-H (amine) 1 to 3 Ar-C-H (benzylic) 2.3 to 2.8 RO-H (alcohol) 0.5 to 5 C=C-H (alkene) 4.5 to 6.5 Ar-O-H (phenol) 6 to 8

Ar-H (benzene) 6.5 to 8.5 -CO2H (carboxylic acid) 10 to 13 O=C-H (aldehyde) 9 to 10

Approximate 13C NMR Chemical Shifts (parts per million)

RCH3 (alkyl) 0 to 35 RCH2Br (alkyl bromide) 20 to 40

R2CH2 (alkyl) 15 to 40 RCH2Cl (alkyl chloride) 25 to 50

R3CH (alkyl) 25 to 50 RCH2NH2 (alkyl amine) 35 to 50

R4C (alkyl) 30 to 40 RCH2OR (alcohol or ether) 50 to 65 R-CC-R (alkyne) 65 to 90 RCN (nitrile) 110 to 125

R2C=CR2 (alkene) 100 to 150 RCO2R (acid, ester) 160 to 185

Benzene C (aromatic) 110 to 175 RCHO, R2CO (ald’hyde, ketone) 190 to 220

Approximate IR Absorption Frequencies (cm-1) Stretching Vibrations -O-H (alcohol) 3200 to 3600 C=C (alkenes) 1620 to 1680 -O-H (carbox. acid) 2500 to 3600 C=O (ald., ketones) 1710 to 1750

RCH=CH2 (alkenes) 910, 990 Monosubstit’d benzene 730 to 770, 690 to 710

R2C=CH2 (alkenes) 890 ortho-disubstit’d benzene 735 to 770

R2C=CHR’ (alkenes) 790 to 840 meta-disubstit’d benzene 750 to 810, 680 to 730 para-disubstituted benzene 790 to 840 Chemistry 3720, Spring 2016 Exam 1 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

1. (8 pts) Give the major products from each step of the reaction sequences below and then show whether the highlighted carbon atoms have been oxidized or reduced in each step by assigning each an oxidation number.

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

4. (8 pts) Draw a complete mechanism for the following ester to ether conversion.

6. (7 pts) Which of the following molecules matches this IR spectrum? Point out important signals that helped you to decide on your choice and why the spectrum does not match the other possibilities.

The strong signal at ~1720 cm-1 indicates a carbonyl which a) and b) don’t have; d) would need an OH at 3300-3600 cm-1.

4 7. (16 pts) In the boxes below, give the major product(s) from each step of the following sequence. The given spectroscopic and molecular formula clues might help you to work out the answers.

8. (9 pts) Draw the structures of each of the following molecules and then provide the reagents needed to convert each of the given starting materials into the required product.

5 9. (8 pts) Within each of the following pairs of molecules circle the one required for the answer and give a few words of explanation for your choice.

10. (8 pts) Provide a suitable organic compound that would serve as a precursor (starting material) for each of the following molecules under the given conditions.

6 Chemistry 3720, Spring 2016 Exam 2 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

#Pi bonds and/or Cycles = [#C - (#H/2) - (#X/2) + #N/2] +1

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

2 3. (9 pts) In the following experiments a diene is reacted with a dienophile at high temperature. Decide which reactions will give a cycloaddition product and which will not. For those that do, draw the structure of the major cycloadduct; for those that do not, give a brief explanation.

4. (8 pts) For the following molecular orbital diagrams used in describing the interactions of reactants in the Diels-Alder reaction, shade in the orbitals as needed to describe the orbital interactions at each energy level. Then populate each set of orbitals with the appropriate number of electrons and indicate in each reactant which orbital is the highest occupied M.O. and which is the lowest unoccupied M.O.

3 5. (18 pts) An unknown organic molecule has been isolated from a tropical plant and is found, from the mass + spectrum, to have the formula C12H13NO and M of 187 atomic mass units. The infra-red spectrum has signals at 2250, 1720, 760, and 690 wavenumbers and the proton and carbon spectra are given below. Provide the structure of the unknown and then indicate which signals belong to which atoms in the 1H NMR spectrum.

1H NMR (ppm): 1.18 (t, 3H, J = 7.0 Hz); 2.60 (t, 2H, J = 6.9 Hz); 2.72 (q, 2H, J = 7.0 Hz); 2.92 (t, 2H, J = 6.9 Hz); 7.32 (t, 1H, J = 6.8 Hz); 7.39 (d, 1H, J = 6.8 Hz); 7.79 (s, 1H); 7.93 (d, 1H, J = 6.8 Hz).

13C NMR (ppm): 11.8 (t); 14.5 (q); 28.2 (t); 34.3 (t); 119.2 (s); 126.0 (d); 127.7 (d); 128.5 (d); 132.1 (d); 136.6 (s); 144.6 (s); 200.1 (s).

4 6. (8 pts) Provide a complete mechanism for the following Friedel-Crafts alkylation that includes resonance structures for the sigma complex that is formed as an intermediate.

7. (7 pts) The proton spectrum below belongs to one of the five molecules given. Indicate which one you think matches the NMR data and explain your choice by pointing out which signal matches which proton(s) and how the coupling constant data helped inform your decision.

1H NMR (ppm): 1.05 (s, 9H); 1.21 (t, 3H, J = 7.0 Hz); 4.06 (q, 2H, J = 7.0 Hz); 5.85 (d, 1H, J = 16 Hz); 6.88 (d, 1H, J = 16 Hz).

5 8. (6 pts) Treatment of the following diene with HBr above room temperature leads to two addition products, one of which is major. Draw the two products and a mechanism for their formation; then explain briefly the isomer distribution observed at this temperature.

9. (6 pts) Benzene is aromatic but cyclobutadiene is antiaromatic. Draw Frost circles for each molecule and use them to explain briefly why benzene is so stable and cyclobutadiene is so unstable.

10. (10 pts) In the boxes provided, draw the expected major product from each step in the following synthetic scheme.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (parts per million)

C C H (alkyne) 2.5 R2N-H (amine) 1 to 3 Ar-C-H (benzylic) 2.3 to 2.8 RO-H (alcohol) 0.5 to 5 C=C-H (alkene) 4.5 to 6.5 Ar-O-H (phenol) 6 to 8

Ar-H (benzene) 6.5 to 8.5 -CO2H (carboxylic acid) 10 to 13 O=C-H (aldehyde) 9 to 10

Approximate 13C NMR Chemical Shifts (parts per million)

RCH3 (alkyl) 0 to 35 RCH2Br (alkyl bromide) 20 to 40

R2CH2 (alkyl) 15 to 40 RCH2Cl (alkyl chloride) 25 to 50

R3CH (alkyl) 25 to 50 RCH2NH2 (alkyl amine) 35 to 50

R4C (alkyl) 30 to 40 RCH2OR (alcohol or ether) 50 to 65 R-CC-R (alkyne) 65 to 90 RCN (nitrile) 110 to 125

R2C=CR2 (alkene) 100 to 150 RCO2R (acid, ester) 160 to 185

Benzene C (aromatic) 110 to 175 RCHO, R2CO (ald’hyde, ketone) 190 to 220

Approximate IR Absorption Frequencies (cm-1) Stretching Vibrations -O-H (alcohol) 3200 to 3600 C=C (alkenes) 1620 to 1680 -O-H (carbox. acid) 2500 to 3600 C=O (ald., ketones) 1710 to 1750

RCH=CH2 (alkenes) 910, 990 Monosubstit’d benzene 730 to 770, 690 to 710

R2C=CH2 (alkenes) 890 ortho-disubstit’d benzene 735 to 770

R2C=CHR’ (alkenes) 790 to 840 meta-disubstit’d benzene 750 to 810, 680 to 730 para-disubstituted benzene 790 to 840 Chemistry 3720, Spring 2016 Exam 2 - Key Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

#Pi bonds and/or Cycles = [#C - (#H/2) - (#X/2) + #N/2] +1

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

13C NMR (ppm): 11.8 (t); 14.5 (q); 28.2 (t); 34.3 (t); 119.2 (s); 126.0 (d); 127.7 (d); 128.5 (d); 132.1 (d); 136.6 (s); 144.6 (s); 200.1 (s).

4 6. (8 pts) Provide a complete mechanism for the following Friedel-Crafts alkylation that includes resonance structures for the sigma complex that is formed as an intermediate.

1H NMR (ppm): 1.05 (s, 9H); 1.21 (t, 3H, J = 7.0 Hz); 4.06 (q, 2H, J = 7.0 Hz); 5.85 (d, 1H, J = 16 Hz); 6.88 (d, 1H, J = 16 Hz).

The 16 Hz coupling constant matches the trans alkene.

The 1,4-adduct is favored here because the higher temperature allows for the additions to be reversible. This will allow for an equilibrium favoring the more stable alkene, i.e. the 1,4-isomer.

9. (6 pts) Benzene is aromatic but cyclobutadiene is antiaromatic. Draw Frost circles for each molecule and use them to explain briefly why benzene is so stable and cyclobutadiene is so unstable.

All of the available electrons in the benzene case go into bonding orbitals and so stabilize this molecule whereas the second pair of electrons in cyclobutadiene have to be split into two separate non-bonding orbitals thereby destabilizing the molecule and making it anti-aromatic.

10. (10 pts) In the boxes provided, draw the expected major product from each step in the following synthetic scheme.

6 Chemistry 3720, Spring 2016 Exam 3 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

#Pi bonds and/or Cycles = [#C - (#H/2) - (#X/2) + #N/2] +1

1. (8 pts) Provide the major product(s) expected to be formed under the following conditions and then draw a detailed mechanism for the process.

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

2 3. (14 pts) In the boxes provided, draw the expected major product from each step in the following synthetic scheme.

4. (8 pts) Provide a product and a complete mechanism for the following reaction that includes resonance structures for the charged complex that is formed as an intermediate.

3 5. (10 pts) An efficient synthesis of the following molecule is not as straightforward as it might appear. Explain why and then give the reagents required to make the molecule in high yield starting from benzene. Give the structures of all intermediate products in your synthesis.

6. (8 pts) Provide the reagents and conditions needed to convert each starting material into the given product. More than one set of reagents may be required in each case.

4 7. (8 pts) In the following reaction two regioisomeric bromides are produced as shown. Decide which product is major, then give a mechanism for its formation, including all important resonance structures. Finally, explain briefly the regioselectivity observed.

8. (8 pts) Provide a mechanism for the following lactone formation that includes all of the important resonance structures for any intermediates that are formed. Explain briefly the role of anhydrous MgSO4 in this process.

5 9. (8 pts) Produce a retrosynthetic analysis for the following molecule that goes back to 1-butanol as the only source of carbon. Then give a synthesis of the molecule that includes structures of any intermediate products that are formed on the way. Assume you have access to any reagents required and that mixtures are separable.

10. (8 pts) In the boxes provided, draw an appropriate starting material that would provide the given products under the conditions shown.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (parts per million)

C C H (alkyne) 2.5 R2N-H (amine) 1 to 3 Ar-C-H (benzylic) 2.3 to 2.8 RO-H (alcohol) 0.5 to 5 C=C-H (alkene) 4.5 to 6.5 Ar-O-H (phenol) 6 to 8

Ar-H (benzene) 6.5 to 8.5 -CO2H (carboxylic acid) 10 to 13 O=C-H (aldehyde) 9 to 10

Approximate 13C NMR Chemical Shifts (parts per million)

RCH3 (alkyl) 0 to 35 RCH2Br (alkyl bromide) 20 to 40

R2CH2 (alkyl) 15 to 40 RCH2Cl (alkyl chloride) 25 to 50

R3CH (alkyl) 25 to 50 RCH2NH2 (alkyl amine) 35 to 50

R4C (alkyl) 30 to 40 RCH2OR (alcohol or ether) 50 to 65 R-CC-R (alkyne) 65 to 90 RCN (nitrile) 110 to 125

R2C=CR2 (alkene) 100 to 150 RCO2R (acid, ester) 160 to 185

Benzene C (aromatic) 110 to 175 RCHO, R2CO (ald’hyde, ketone) 190 to 220

Approximate IR Absorption Frequencies (cm-1) Stretching Vibrations -O-H (alcohol) 3200 to 3600 C=C (alkenes) 1620 to 1680 -O-H (carbox. acid) 2500 to 3600 C=O (ald., ketones) 1710 to 1750

RCH=CH2 (alkenes) 910, 990 Monosubstit’d benzene 730 to 770, 690 to 710

R2C=CH2 (alkenes) 890 ortho-disubstit’d benzene 735 to 770

R2C=CHR’ (alkenes) 790 to 840 meta-disubstit’d benzene 750 to 810, 680 to 730 para-disubstituted benzene 790 to 840 Chemistry 3720, Spring 2016 Exam 3 - Key Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

#Pi bonds and/or Cycles = [#C - (#H/2) - (#X/2) + #N/2] +1

1. (8 pts) Provide the major product(s) expected to be formed under the following conditions and then draw a detailed mechanism for the process.

1 2. (20 pts) Draw the expected major products from each step of the following reaction sequences. Make sure you take into account any stereochemical changes where applicable.

2 3. (14 pts) In the boxes provided, draw the expected major product from each step in the following synthetic scheme.

4. (8 pts) Provide a product and a complete mechanism for the following reaction that includes resonance structures for the charged complex that is formed as an intermediate.

6. (8 pts) Provide the reagents and conditions needed to convert each starting material into the given product. More than one set of reagents may be required in each case.

10. (8 pts) In the boxes provided, draw an appropriate starting material that would provide the given products under the conditions shown.

6 Chemistry 3720, Spring 2016 Final Exam Student Name:

“Y” Number:

This exam is worth 200 points out of a total of 700 points for Chemistry 3720/3720L. You have 120 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (9 pts) For the following Baeyer-Villager reaction, give a complete mechanism, including any resonance structures, for the conversion of the ketone into the final product. Explain the observed regioselectivity.

1 2. (9 pts) Provide a detailed mechanism for the following Wittig synthesis that includes resonance structures for any intermediates that are formed.

1. PPh , ether H3C Br 3 CH3 2. LDA, THF

3. O

H3C CH3

3. (9 pts) Draw a complete mechanism for the following Gabriel amine synthesis that includes any resonance structures for intermediates that are formed.

2 4. (10 pts) Provide a detailed mechanism for the following Robinson synthesis that includes all important resonance structures for intermediates that are formed. Use “R” groups for brevity where possible.

5. (8 pts) Give the two major products that are formed from the following crown ether under the conditions provided and then a detailed mechanism for their formation.

3 6. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to take tautomerism into consideration where applicable.

4 7. (14 pts) In the boxes below, provide the major product from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

8. (8 pts) One of the most common organic polymers used in 3D printing is polylactic acid (PLA), which is derived from corn and is biodegradable. Provide a detailed mechanism, including any important resonance structures for how the two lactic acid units shown below come together to give the polymer linkage.

5 9. (15 pts) For the following multi-step laboratory synthesis of the amino acid (+/-)-proline, provide detailed mechanisms, including important resonance structures, for steps A, C, E, F and G.

CN O O O O

O O Ni/H2 EtO OEt EtO OEt HN CO Et EtO OEt NaOEt (- EtOH) 2 O ABCCN NH2

+ SOCl2 Cl H3O , Cl i. HO i. HO HN NH3 CO2Et (- CO ) CO2H ii. HCl N CO2H N CO2 2 H H O Cl 2 D EFG

6 10. (12 pts) Provide a retrosynthesis for this molecule that goes back to 1-butanol as the only source of carbon. Then build the molecule in the forward direction showing the product from each step.

11. (10 pts) The 1H spectrum below belongs to one of the five molecules given. Indicate which one you think matches the NMR data and explain your choice by pointing out which signal matches which proton(s).

O O

O O O

8 7 6 5 4 3 2 1 0 PPM

1H NMR (ppm): 0.98 (d, 6H, J = 7.0 Hz); 1.18 (t, 3H, J = 6.9 Hz); 2.21 (multiplet, 1H, J = 7.0 Hz); 2.72 (q, 2H, J = 6.9 Hz); 2.88 (d, 2H, J = 7.0 Hz); 6.80 (d, 2H, J = 6.8 Hz); 6.90 (s, 2H, J = 6.8 Hz). 7 12. (12 pts) For each of the following series of molecules, circle the one that is asked for, then give a brief explanation for your choices.

13. (8 pts) Give the major product(s) expected to be formed under the following conditions, and then draw a detailed mechanism that includes any important resonance structures. Why is/are your product(s) major?

8 14. (16 pts) An unknown organic compound has the molecular formula C11H14O3; the mass spectrum shows M+ = 194.09 a.m.u., the IR spectrum shows significant signals at 1740, 1200, and 800 cm-1, and the 1H and 13C NMR spectra are given below. Suggest a structure for the unknown molecule that matches the data and then indicate which signals belong to which protons in the 1H NMR spectrum.

9 8 7 6 5 4 3 2 1 0 PPM

1 H NMR (CDCl3) ppm : 1.01 (t, 3H, J = 7.1 Hz), 1.91 (sextet, 2H, J = 7.1 Hz), 3.81 (singlet, 3H), 4.30 (t, 2H, J = 7.1 Hz), 6.85 (d, 2H, J = 6.8 Hz), 7.94 (d, 2H, J = 6.8 Hz).

180 160 140 120 100 80 60 40 20 0 PPM

13 C NMR (CDCl3) ppm : 10.3 (q), 21.9 (t), 55.8 (q), 68.8 (t), 114.2 (d), 122.4 (s), 130.9 (d), 164.9 (s), 165.9 (s)

9 15. (8 pts) Indicate which product will be major, then give a detailed mechanism for its formation that includes resonance structures for any intermediates that are formed. Why is that product major?

16. (10 pts) Give a complete mechanism for this process that includes any important resonance structures.

10 17. (12 pts) Give the products from each step of the following synthetic sequence and then, on the NMR axis given below, draw the expected 1H spectrum of the final product.

18. (10 pts) The following molecule is lactose, which is found in milk, and is made up of one galactose and one + glucose subunit. When this molecule is treated with H /H2O it is hydrolyzed to the two individual monosaccharides. Draw structures of the D-galactose and D-glucose products and a mechanism for their formation, including any important resonance structures.

11 Spring 2015

Page File 106 Spring 2015 Exam 1 113 Spring 2015 Exam 1 Key 119 Spring 2015 Exam 2 126 Spring 2015 Exam 2 Key 132 Spring 2015 Exam 3 138 Spring 2015 Exam 3 Key 144 Spring 2015 Final (No Key)

Chemistry 3720, Spring 2015 Exam 1 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached at the back of the exam. Good Luck!

1. (8 pts) Provide the product(s) expected from each step of the following reaction sequence as well as detailed mechanisms for each step in the conversion of starting materials to product(s).

1 2. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to include any stereochemical changes where applicable.

O 1. NaBH4,CH3OH a. 2. NaH, THF O 3. CH3Br

CH3 1. m-CPBA, CH2Cl2 b. 2. PhMgBr, THF

3. NH4Cl (aq)

OH 1. PDC, CH2Cl2 c. 2. CH3MgBr, ether + 3. H3O (quench)

1. xs CH3MgBr, ether d. OMe + 2. H3O (quench) + - 3. (C4H9)4N F OSiMe3

Me OH 1. PCC, CH2Cl2 e. 2. TsCl, pyridine OH 3. KOtBu, THF

2 3. (9 pts) Give the products expected to be formed from each step under the following conditions. Then draw complete mechanisms for each of the conversions.

4. (8 pts) From the molecules shown below, choose which one matches the following mass spectrum. Then explain your choice, including reasons for why you didn’t pick the other possible answers. Atomic masses (in atomic mass units, a.m.u.) are as follows: C = 12 ; H = 1 ; O = 16 ; F = 19 ; Cl = 35.45 ; Br = 79.90.

OH Br Cl F a) b) c) d)

CH3 CH3 CH3 CH3

3 5. (14 pts) In the boxes below, provide the product(s) from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you come up with answers.

6. (8 pts) Give the major product(s) expected to be formed under the following conditions as well as a complete mechanism for its/their formation.

4 7. (8 pts) Give the expected product(s) from each step of the following reaction sequence, and then provide a mechanism for each synthetic step.

8. (8 pts) Provide a retrosynthesis for the following ether that goes back to the sources of carbon shown. Then show how you would make the target molecule using any of the reactions seen so far in Chemistry 3719/ 3720. Include a product from each of your synthetic steps.

5 9. (9 pts) Which of the following molecules does the IR spectrum below match? Explain your choice here by pointing out important signals that helped you to decide on your choice and why the spectrum does not match the other possibilities (Use the spectroscopy sheet for numbers).

10. (8 pts) For the following multi-step synthesis, give the product expected from each step as well as complete mechanisms that describe all of the major events on the way from starting material to the final product.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (δ, ppm)

R3C-H (alkyl) 0.9-1.8 R3N-C-H (N neighbor) 2.2-2.9

C=C-C-H (allylic) 1.6-2.6 Cl-C-H (Cl neighbor) 3.1-4.1

O=C-C-H (α to C=O) 2.1-2.5 Br-C-H (Br neighbor) 2.7-4.1

NC-C-H (α to CN) 2.1-3.0 -O-C-H (O neighbor) 3.3-3.7

CCH (alkyne) 2.5 R2N-H (amine) 1-3

Ar-C-H (benzylic) 2.3-2.8 RO-H (alcohol) 0.5-5

C=C-H (alkene) 4.5-6.5 Ar-O-H (phenol) 6-8

Ar-H (benzene) 6.5-8.5 -CO2H (carboxylic acid) 10-13

O=C-H (aldehyde) 9-10

Approximate 13C NMR Chemical Shifts (δ, ppm)

RCH3 (alkyl) 0-35 RCH2Br (alkyl bromide) 20-40

R2CH2 (alkyl) 15-40 RCH2Cl (alkyl chloride) 25-50

R3CH (alkyl) 25-50 RCH2NH2 (alkyl amine) 35-50

R4C (alkyl) 30-40 RCH2OR (alcohol or ether) 50-65

RRCC (alkyne) 65-90 RCN (nitrile) 110-125

R2C=CR2 (alkene) 100-150 RCO2R (acid, ester) 160-185

Benzene C (aromatic) 110-175 RCHO, R2CO (aldehyde, ketone) 190-220

Approximate IR Absorption Frequencies (cm-1)

Stretching Vibrations

-O-H (alcohol) 3200-3600 C=C (alkenes) 1620-1680 -O-H (carbox. acid) 2500-3600 C=O (ald., ketones) 1710-1750 R2N-H (amine) 3350-3500 C=O (acyl halides) 1770-1815 sp C-H (alkynes) 3310-3320 C=O (esters) 1730-1750 sp2 C-H (alkenes) 3000-3100 C=O (amides) 1680-1700 sp3 C-H (alkanes) 2850-2950 sp2 C-O (carbonyls) 1200 triple bond (alkynes) 2100-2200 sp3 C-O (alcoh., ethers) 1025-1200 triple bond (nitriles) 2240-2280

Bending Vibrations

RCH=CH2 (alkenes) 910, 990 Monosubstituted benzene 730-770, 690-710 R2C=CH2 (alkenes) 890 ortho-disubstituted benzene 735-770 R2C=CHR’ (alkenes) 790-840 meta-disubstituted benzene 750-810, 680-730 para-disubstituted benzene 790-840 Chemistry 3720, Spring 2015 Exam 1 - Key Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached at the back of the exam. Good Luck!

1. (8 pts) Provide the product(s) expected from each step of the following reaction sequence as well as detailed mechanisms for each step in the conversion of starting materials to product(s).

HO OH O 1. xs LiAlH4,THF H O H 2. H2O

[H AlH3] HOH HOH

O O O H O H H O O H

[H AlH3]

1 2. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to include any stereochemical changes where applicable.

O 1. NaBH4,CH3OH 1. OH 2.O 3. OCH3 a. 2. NaH, THF O O O O 3. CH3Br (+/-) (+/-)(+/-)

1. 2. 3. CH3 CH3 CH3 CH3 1. m-CPBA, CH2Cl2 b. O OH O 2. PhMgBr, THF Ph Ph 3. NH4Cl (aq) (+/-) (+/-) (+/-)

1. O OH OH 1. PDC, CH2Cl2 O 2. 3. c. CH3 CH3 2. CH3MgBr, ether + 3. H3O (quench) (+/-) (+/-)

O O OH OH 1. 2. 3. 1. xs CH3MgBr, ether d. OMe CH3 CH3 CH3 + CH3 CH3 CH3 2. H3O (quench) + - 3. (C4H9)4N F OSiMe3 OSiMe3 OSiMe3 OH

Me 1. Me 2.Me 3. OH 1. PCC, CH2Cl2 OH OTs Me e. 2. TsCl, pyridine OH O O O 3. KOtBu, THF

2 3. (9 pts) Give the products expected to be formed from each step under the following conditions. Then draw complete mechanisms for each of the conversions.

CH2Br CH2SCH2CH2CH3 1. NaSH, DMF

2. NaH, THF 3. CH3CH2CH2Br

CH2S H CH2S Na :H

Each of the four possible answers would give the same base peak at m/z = 92 by losing the X atom/group from the methylbenzene ring, however only the bromo derivative would have M and M+2 signals due to the two naturally occurring isotopes of bromine. The approximately equal intensity of the two signals at 170 and 172 confirm this.

3 5. (14 pts) In the boxes below, provide the product(s) from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you come up with answers.

6. (8 pts) Give the expected major product(s) expected to be formed under the following conditions as well as a complete mechanism for its/their formation.

2 The benzene ring will not undergo substitution since SN1 and SN2 reactions do not occur at sp C.

4 7. (8 pts) Give the expected product(s) from each step of the following reaction sequence, and then provide a mechanism for each synthetic step.

Retrosynthesis Br HO O O OH

Br MgBr

OH H Synthesis O PCC HO H CH2Cl2 OMgBr OH aq. NH4Cl

Br Mg MgBr

ether NaH, THF

O ONa PBr3 HO Br Br

The strong, broad signal at ~3300 cm-1 indicates an OH group, most likely in an alcohol. The carboxylic acid would have a C=O signal around ~1750, which is absent here; the ether would not have the strong OH signal at ~3300 ; the ketone would show a strong C=O signal at ~1730, which is absent here.

6 Chemistry 3720, Spring 2015 Exam 2 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached at the back of the exam. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (9 pts) Provide the product(s) from each step of this reaction sequence as well as detailed mechanisms for each step in the conversion of starting materials to product. Then draw the 1H NMR of the product.

1 2. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to include any stereochemical changes where applicable.

O 1. PhMe, reflux a. + H 2. Na2Cr2O7,H2SO4

1. Br2, heat b. 2. KOtBu 3. m-CPBA

O 1. Zn, HCl c. 2. Na2Cr2O7,H2SO4

1. HBr d. 2. NaCN, DMF

1. HNO3,H2SO4 e. OH 2. Sn, HCl

2 3. (9 pts) Using Hűckel’s rule and Frost circles, indicate which of the following molecules will be aromatic and which will be anti-aromatic. Include the Hűckel calculation in each of your answers.

4. (9 pts) Which one of the following compounds matches the spectral data given below? Your answer should include reasoning for why you picked that compound and not the others.

a. b. c. O O O

OH OH

d. OH e. f. O O O O O

1 H NMR (CDCl3) ppm: 1.05 (s, 9H), 5.83 (d, 1H, J = 16 Hz), 6.71 (d, 1H, J = 16 Hz), 7.31-7.44 (m, 5H).

13 C NMR (CDCl3) ppm: 29.5 (q, triple intensity), 32.9 (s), 114.5 (d), 121.6 (d, double intensity), 125.5 (d), 129.1 (d, double intensity), 151.3 (s), 158.2 (d), 164.3 (s).

3 5. (14 pts) In the boxes below, provide the major product from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

CH3COCl, AlCl3 NaBH4,CH3OH

-1 IR : 1740 cm [ ]D =0

PBr3

D2O Mg, ether

1 + H NMR: 0.98, 3H d C8H9MgBr MS: M = 184, M+2 = 186

Cl ,AlCl3

Zn, HCl Final product:

Molecular formula = C13H19D

13C NMR: 9 signals

6. (8 pts) Give the major and minor product expected to be formed under the following conditions as well as a complete mechanism for their formation. Explain the major/minor distribution at this reaction temperature.

4 7. (14 pts) An unknown organic compound has the molecular formula C13H18O2; the mass spectrum shows M+ = 206 a.m.u., the IR spectrum shows significant signals at 1720, 1200, and 800 cm-1, and the 1H and 13C NMR spectra are given below. Suggest a structure for the unknown molecule that matches the data and then indicate which signals belong to which protons in the 1H NMR spectrum.

1 H NMR (CDCl3) ppm : 0.98 (t, 3H, J = 7.1 Hz), 1.29 (d, 6H, J = 7.0 Hz), 1.51 (sextet, 2H, J = 7.1 Hz), 2.96 (t, 2H, J = 7.1 Hz), 4.69 (septet, 1H, J = 7.0 Hz), 7.01 (d, 2H, J = 7.5 Hz), 7.92 (d, 2H, J = 7.5 Hz).

13 C NMR (CDCl3) ppm : 13.6 (q), 17.4 (t), 22.0 (q, double intensity), 40.4 (t), 75.8 (d), 114.3 (d, double intensity), 129.4 (d, double intensity), 130.8 (s), 161.8 (s), 200.1 (s)

5 8. (9 pts) Provide a detailed mechanism for the following transformation that includes all important resonance structures for the intermediate involved. Then explain, briefly, the observed regioselectivity.

C N C N

Br2,FeBr3

9. (8 pts) Which of the following diene compounds do you expect to participate in Diels-Alder reactions and which will not? Explain your choices.

6 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (δ, ppm)

R3C-H (alkyl) 0.9-1.8 R3N-C-H (N neighbor) 2.2-2.9

C=C-C-H (allylic) 1.6-2.6 Cl-C-H (Cl neighbor) 3.1-4.1

O=C-C-H (α to C=O) 2.1-2.5 Br-C-H (Br neighbor) 2.7-4.1

NC-C-H (α to CN) 2.1-3.0 -O-C-H (O neighbor) 3.3-3.7

CCH (alkyne) 2.5 R2N-H (amine) 1-3

Ar-C-H (benzylic) 2.3-2.8 RO-H (alcohol) 0.5-5

C=C-H (alkene) 4.5-6.5 Ar-O-H (phenol) 6-8

Ar-H (benzene) 6.5-8.5 -CO2H (carboxylic acid) 10-13

O=C-H (aldehyde) 9-10

Approximate 13C NMR Chemical Shifts (δ, ppm)

RCH3 (alkyl) 0-35 RCH2Br (alkyl bromide) 20-40

R2CH2 (alkyl) 15-40 RCH2Cl (alkyl chloride) 25-50

R3CH (alkyl) 25-50 RCH2NH2 (alkyl amine) 35-50

R4C (alkyl) 30-40 RCH2OR (alcohol or ether) 50-65

RRCC (alkyne) 65-90 RCN (nitrile) 110-125

R2C=CR2 (alkene) 100-150 RCO2R (acid, ester) 160-185

Benzene C (aromatic) 110-175 RCHO, R2CO (aldehyde, ketone) 190-220

Approximate IR Absorption Frequencies (cm-1)

Stretching Vibrations

Bending Vibrations

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached at the back of the exam. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (9 pts) Provide the product(s) expected from each step of the following reaction sequence as well as detailed mechanisms for each step in the conversion of starting materials to product.

1 2. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to include any stereochemical changes where applicable.

O O O O O 1. PhMe, reflux 1. 2. a. + H H H OH OH 2. Na2Cr2O7, H2SO4 + +

major (endo) major (exo)

Br O 1. 2. 3. 1. Br2, heat b. 2. KOtBu

3. m-CPBA (+/-) (+/-)

O H H O 1. Zn, HCl 1. 2. c. OH 2. Na2Cr2O7, H2SO4

Br CN 1. HBr 1. 2. d. 2. NaCN, DMF

(+/-) (+/-)

O O O

1. HNO3, H2SO4 1. 2. e. OH OH OH 2. Sn, HCl

NO2 NH2

a. 6 pi electrons, therefore 4n+2 =6; n =1 only bonding M.O. integer + flat, fully conjugated = aromatic are populated

b. 6 pi electrons, therefore 4n+2 =6; n =1 only bonding M.O. integer + flat, fully conjugated = aromatic are populated

c. 4 pi electrons, therefore 4n+2 =4; n =1/2 non-bonding M.O. non-bonding orbitals half full = antiaromatic half-populated

4. (9 pts) Which one of the following compounds matches the spectral data given below? Your answer should include reasoning for why you picked that compound and not the others.

a. b. c. O O O

OH OH

d. OH e. f. O O O O O

1 H NMR (CDCl3) ppm: 1.05 (s, 9H), 5.83 (d, 1H, J = 16 Hz), 6.71 (d, 1H, J = 16 Hz), 7.31-7.44 (m, 5H).

13 C NMR (CDCl3) ppm: 29.5 (q, triple intensity), 32.9 (s), 114.5 (d), 121.6 (d, double intensity), 125.5 (d), 129.1 (d, double intensity), 151.3 (s), 158.2 (d), 164.3 (s).

5.83 1.05 29.5 1.05 H 29.5 114.5 121.6 7.33 32.9 164.3O151.3 O 7.44 129.1 1.05 29.5 158.2 O H O 7.33 7.31 121.6 125.5 6.71 7.44 129.1

13C signal at 164.3 indicates an ester so compounds a, c, and d don’t fit. Compound f would have three 1H signals for the alkene; the J value of 16 Hz indicates the trans alkene in compound e and not cis in b.

3 5. (14 pts) In the boxes below, provide the major product from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

O OH CH3COCl, AlCl3 NaBH4, CH3OH

-1 IR : 1740 cm [ ]D = 0

PBr3

D MgBr Br D2O Mg, ether

1 + H NMR: 0.98, 3H d C8H9MgBr MS: M = 184, M+2 = 186

Cl , AlCl3

D D Zn, HCl Final product:

Molecular formula = C13H19D O H H 13C NMR: 9 signals

13 C NMR (CDCl3) ppm : 13.6 (q), 17.4 (t), 22.0 (q, double intensity), 40.4 (t), 75.8 (d), 114.3 (d, double intensity), 129.4 (d, double intensity), 130.8 (s), 161.8 (s), 200.1 (s)

2.96 O 0.98 1.51 7.92 7.92

7.01 7.01

1.29 4.69 O

1.29 5 8. (9 pts) Provide a detailed mechanism for the following transformation that includes all important resonance structures for the intermediate involved. Then explain, briefly, the observed regioselectivity.

9. (8 pts) Which of the following diene compounds do you expect to participate in Diels-Alder reactions and which will not? Explain your choices.

a. Will react in Diels-Alder reactions since the diene is conjugated and trapped in the required s-cis conformation.

b. Will not participate in Diels-Alder reactions since the diene, even though conjugated, is trapped in the s-trans orientation.

c. Will not participate in Diels-Alder reactions since the diene is not conjugated; the alkenes are isolated.

d. Will participate in Diels-Alder reactions since the diene is both conjugated and can rotate to the required s-cis conformation.

6 Chemistry 3720, Spring 2015 Exam 3 Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached at the back of the exam. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (8 pts) Provide a complete mechanism for the following conversion that includes resonance structures for any intermediates that are formed. What experimental measures would you take to push this reaction completely to product?

1 2. (9 pts) Starting with benzene, provide a synthesis of methyl 3-aminobenzoate using any of the chemistry and reagents seen thus far in 3719 and 3720. Show the major product from each step; however you do not need to show a retrosynthesis unless it helps you to develop the synthetic route.

3. (10 pts) Draw a complete mechanism for the following sequence that includes all resonance structures for any intermediates that are formed along the reaction profile.

2 4. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to include any stereochemical changes where applicable.

O 1. SOCl2 a. OH 2. HN(CH2CH3)2

3. LiAlH4, then H2O

OH 1. PCC, CH2Cl2 b. + 2. NH2NH2,cat.H

3. KOH, H2O, reflux

O 1. HNO3,H2SO4 c. 2. NaBH4,CH3OH 3. Sn, HCl

1. Na2Cr2O7,H2SO4 d. + 2. xs. CH3OH, cat. H

3. Br2,FeBr3

OMe + 1. H3O (hydrolysis) e. OMe 2. PhMgBr, ether + 3. H quench

3 5. (14 pts) In the boxes below, provide the major product from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

O NaBH4,CH3OH PBr3 H

-1 IR : 3200 cm C7H7Br

NaCN, DMF

+ SOCl2 H /H2O/

24 hours

acid chloride IR : 3200, 1740 cm-1 IR : 2250 cm-1

CH3OH, pyridine

H-Al(i-Bu)2 Final product:

then H+ workup Molecular formula = C8H8O

13C NMR: 7 signals

6. (7 pts) Provide a complete mechanism for the following transformation that includes all resonance structures for the intermediate that is formed.

4 7. (8 pts) Give a complete mechanism for the following nitrile hydrolysis that includes all important resonance structures for any intermediates that are formed.

8. (8 pts) By using curved arrows, show how the following aldol transformation occurs. Draw all important resonance structures where applicable.

5 9. (8 pts) Draw a complete mechanism for the following alpha-bromination reaction that includes all resonance structures for any intermediates that formed along the way from starting material to product.

10. (8 pts) Give the structure of the major product expected from each step in the following synthetic sequence. No need to show mechanisms here.

1. PCC, CH2Cl2

2. Br2,FeBr3 OH + 3. xs CH3OH, cat. H 4. Mg, ether

5. D2O + 6. H /H2O (hydrolyze)

7. PPh3

6 Chemistry 3720, Spring 2015 Exam 3 - Key Student Name:

“Y” Number:

This exam is worth 100 points out of a total of 700 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam. The spectroscopy sheet is attached at the back of the exam. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

cat. H+ ROH

H H O O OOH

HOCH2CH2OH

OH OH OH

H OH OH O O + O 2 H trans -H2O

Use a drying agent like anhydrous MgSO4 to remove the water and push the equilibrium to product.

3. (10 pts) Draw a complete mechanism for the following sequence that includes all resonance structures for any intermediates that are formed along the reaction profile.

NH2 O N H H H+ NH2NH2 KOH, H2O cat. H+ heat

H H H H O NH NH O HO N 2 H2O N 2 H NH2NH2 H+ trans

H H H

H NH H NH2 N N N N 2 N N H N N

+ -H2O -H OH

HO H H N N H N H N H H H OH -N2 H OH

2 4. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to include any stereochemical changes where applicable.

O O O H H 1. SOCl2 1. 2. 3. a. OH Cl NEt2 NEt2 2. HN(CH2CH3)2

3. LiAlH4, then H2O

OH O NNH2 H H 1. 3. 1. PCC, CH2Cl2 2. b. + 2. NH2NH2,cat.H

3. KOH, H2O, reflux

O O OH OH 1. 1. HNO3,H2SO4 2. 3. c. 2. NaBH4,CH3OH 3. Sn, HCl NO2 NO2 NH2

O O O 1. 1. Na2Cr2O7,H2SO4 2. 3. d. OH OCH3 OCH3 + 2. xs. CH3OH, cat. H

3. Br2,FeBr3 Br

OMe O O Ph HO Ph + 1. 2. 3. 1. H3O (hydrolysis) e. OMe H H H 2. PhMgBr, ether + 3. H quench

3 5. (14 pts) In the boxes below, provide the major product from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

6. (7 pts) Provide a complete mechanism for the following transformation that includes all resonance structures for the intermediate that is formed.

4 7. (8 pts) Give a complete mechanism for the following nitrile hydrolysis that includes all important resonance structures for any intermediates that are formed.

+ O N H /H2O/ C 24 hours OH H+ -H+

H H OH OH OH N N C C C C C OH OH OH

H2O

NH NH2 NH2 H+ trans NH3 C C C C OH2 OH OH OH OH2 OH

OH2

NH2 NH2 C C OH OH

8. (8 pts) By using curved arrows, show how the following aldol transformation occurs. Draw all important resonance structures where applicable.

O NaOCH3,CH3OH H O

H reflux H H

_ CH3O OH

O O H OH O H OH O H H H H

H H H O O HOCH3 H OH O

H H OCH3 H

O O + Br2/H3O Br H+

-H+ H H H H O O O O

H OH2 Br Br

H O

Br Br

10. (8 pts) Give the structure of the major product expected from each step in the following synthetic sequence. No need to show mechanisms here.

6 Chemistry 3720, Spring 2015 Final Exam Student Name:

“Y” Number:

This exam is worth 200 points out of a total of 700 points for Chemistry 3720/3720L. You have 120 minutes to complete the exam. The spectroscopy sheet is attached as the last page. Good Luck!

HDI/Unsaturation Number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (8 pts) For the following Wittig reaction sequence, give the products expected from each step and then a complete mechanism for the conversion of the alkyl halide into the final product.

1 2. (8 pts) A new medicinal compound, isolated from a tropical plant, has one of the following structures. Using the provided spectral data, indicate which structure is correct and then explain your decision by matching the data to the structure.

Selected data: IR : 3350, 3000, 1690 cm-1 ; 13C NMR : 170, 150, 120 ppm ; 1H NMR : 6.0 ppm (s, 1H)

3. (8 pts) In the following reaction one major product is formed with molecular formula C7H5N3O6. The molecule has 5 signals in its 13C NMR spectrum and 2 signals in the 1H NMR. Draw the product; give a mechanism for the first nitration, and finally a brief explanation for the observed regioselectivity.

2 4. (8 pts) Provide a detailed mechanism for the following prostaglandin synthesis that includes all important resonance structures for intermediates that are formed. Use “R” groups for brevity where possible.

5. (8 pts) Draw a detailed mechanism for the following ester conversion that includes all important resonance structures for any intermediates that are formed.

3 6. (20 pts) Provide the expected major products from each step of the following reaction sequences. Be sure to take tautomerism into consideration where applicable.

O + 1. Br2,H3O a. 2. KOt-Bu

3. NaBH4,CH3OH

OH 1. PCC, CH2Cl2 b. 2. LDA, THF

3. CH3CH2CH2Br

O 1. (CH3)2CuLi, THF c. 2. H+ quench

3. NaBH4,CH3OH

O 1. H2,Pd d. + 2. NH2NH2,cat.H

3. KOH, D2O,

O 1. PhMgBr, ether e. 2. H+ quench 3. m-CPBA, CH2Cl2

4 7. (14 pts) In the boxes below, provide the major product from each step of the following sequence. Using the spectroscopic and molecular formula clues might help you to come up with answers.

Na2Cr2O7,H2SO4 SOCl2 OH

-1 IR : 2700, 1740 cm C2H3ClO

EtOH, pyridine

H+ quench NaOEt, EtOH

-1 -1 IR 1750, 1710 cm C6H9NaO3 IR : 1740 cm

NaBH4,EtOH

(CH3)3SiCl Final product:

Et3N Molecular formula = C9H20O3Si

IR 3300, 1740 cm-1

6. (8 pts) Provide a complete mechanism for the following transformation that explains how the two regioisomeric products are formed.

5 7. (9 pts) Starting with benzene, provide an efficient synthesis of 4-nitrobenzoic acid that employs any of the chemistry seen throughout Chemistry 3719 and 3720. Provide the product from each step.

8. (10 pts) Give a retrosynthesis for this molecule that goes back to cyclohexanol and ethanol as the only sources of carbon. Then build the molecule in the forward direction showing the product from each step.

6 9. (8 pts) Draw Frost circles and apply Hückel’s rule to decide if each of the following molecules is aromatic or not. You need to show the results of your Hückel calculations for full credit.

10. (8 pts) Draw the structure of the monomer precursor that would be needed to produce each of the four polymers below. Label each polymer as being either the “addition” or “condensation” type.

H CH3 O H b. N N N

O H CH3 O

O O c. O O O O O

7 11. (8 pts) Draw a complete mechanism for the following cyclization process that includes all resonance structures for any intermediates that formed along the way from starting material to product. Use “R” groups to abbreviate structures as appropriate.

12. (8 pts) Give the structure of the major product expected from each step in the following synthetic sequence as well as detailed mechanisms for their formation.

O 1. KOH, EtOH Br N H 2.

O 3. NH2NH2

8 13. (14 pts) An unknown organic compound has the molecular formula C11H14O2; the mass spectrum shows M+ = 178.10 a.m.u., the IR spectrum shows significant signals at 1740, 1050, 760 and 690 cm-1, and the 1H and 13C NMR spectra are given below. Suggest a structure for the unknown molecule that matches the data and then indicate which signals belong to which protons in the 1H NMR spectrum.

1 H NMR (CDCl3) ppm : 1.20 (d, 6H, J = 7.1 Hz), 2.87 (septet, 1H, J = 7.1 Hz), 3.89 (singlet, 3H), 7.35 (t, 1H, J = 7.5 Hz), 7.49 (d, 1H, J = 7.5 Hz), 7.89 (d, 1H, J = 7.5 Hz), 7.99 (s, 1H).

13 C NMR (CDCl3) ppm : 23.3 (q, double intensity), 33.2 (d), 51.5 (q), 127.1 (d), 127.2 (d), 128.3 (d), 129.8 (s), 130.4 (d), 150.0 (s), 165.9 (s)

9 14. (7 pts) Provide a complete mechanism for the following Baeyer-Villiger oxidation. Then try to explain the regioselectivity observed in this reaction.

15. (7 pts) Give a detailed mechanism for the following reductive amination reaction that includes resonance structures for any intermediates that are formed.

16. (7 pts) Draw a detailed mechanism for the following cyclization reaction that includes resonance structures for any intermediates that are formed.

10 17. (8 pts) Provide a complete mechanism for the following “iodoform” reaction that includes all resonance structures for any intermediates that are formed.

18. (8 pts) Give the expected products for the two epoxide reactions shown below as well as mechanisms for their formation that include any important resonance structures. How do your mechanisms explain the observed optical rotation data?

11 19. (8 pts) For the following Robinson annulation, provide a detailed step-by-step mechanism that explains the formation of the third cycle. Include resonance structures where relevant.

20. (8 pts) The following molecule is a pentasaccharide that induces antibodies to epithelial cancer cells when + conjugated to various proteins. When this molecule is treated with H /H2O it is hydrolyzed to the five individual monosaccharides by cleavage of each of the acetal linkages. Circle each acetal carbon in the pentasaccharide and then draw the five reducing sugars expected to be formed after acetal hydrolysis.

12 Youngstown State University Organic Chemistry Spectral Data Sheet

Approximate 1H NMR Chemical Shifts (δ, ppm)

R3C-H (alkyl) 0.9-1.8 R3N-C-H (N neighbor) 2.2-2.9

C=C-C-H (allylic) 1.6-2.6 Cl-C-H (Cl neighbor) 3.1-4.1

O=C-C-H (α to C=O) 2.1-2.5 Br-C-H (Br neighbor) 2.7-4.1

NC-C-H (α to CN) 2.1-3.0 -O-C-H (O neighbor) 3.3-3.7

CCH (alkyne) 2.5 R2N-H (amine) 1-3

Ar-C-H (benzylic) 2.3-2.8 RO-H (alcohol) 0.5-5

C=C-H (alkene) 4.5-6.5 Ar-O-H (phenol) 6-8

Ar-H (benzene) 6.5-8.5 -CO2H (carboxylic acid) 10-13

O=C-H (aldehyde) 9-10

Approximate 13C NMR Chemical Shifts (δ, ppm)

RCH3 (alkyl) 0-35 RCH2Br (alkyl bromide) 20-40

R2CH2 (alkyl) 15-40 RCH2Cl (alkyl chloride) 25-50

R3CH (alkyl) 25-50 RCH2NH2 (alkyl amine) 35-50

R4C (alkyl) 30-40 RCH2OR (alcohol or ether) 50-65

RRCC (alkyne) 65-90 RCN (nitrile) 110-125

R2C=CR2 (alkene) 100-150 RCO2R (acid, ester) 160-185

Benzene C (aromatic) 110-175 RCHO, R2CO (aldehyde, ketone) 190-220

Approximate IR Absorption Frequencies (cm-1)

Stretching Vibrations

Bending Vibrations