Mock Exam 2 CH 237-2F March 8, 2015
Multiple Choice
1. Which of the following methods will give a carboxylic acid as the final product?
a. Reaction of a Grignard reagent with CO2 b. Reacting an aldehydye with LiAlH4 c. Hydrolysis of an amide d. Both A and C e. Both B and C
2. Diisobutylaluminum hydride (DIBALH) can be used to carry out which of the following conversions? a. Secondary alcohol to ketone b. Ester to aldehyde c. Carboxylic acid to ester d. Aldehyde to carboxylic acid e. Ester to Ketone
3. Rank the following compounds in order of decreasing acidity. (most to least)
I II III IV V
a. I>V>IV>III>II b. II>III>IV>I>V c. III>II>V>IV>I d. II>III>V>IV>I e. III>II>IV>V>I
4. Which of the following compounds contains the best leaving group?
a. Carboxylic Acid b. Ester c. Acid Anhydride d. Acid Chloride e. Amide
5. Choose the method(s) that can be used to synthesize the alcohol shown below:
1)CH3MgBr, ether
+ 2)H
1)2-propanone
2)H+
1)CH3MgBr, ether
2)H+
a. II only b. I, II c. II, III d. I, III e. All three will work. I am not sure if you assume that there is excess Grignard for the first one, I will ask and let you all know.
6. Which of the following will not give a carboxylic acid upon treatment with aqueous acid?
a. b. c. d. e. More than one is correct
7. Which of the following is not true regarding the conjugation of 1,3-butadiene?
a. All atoms are sp2 hybridized. b. The C-C single bond is shorter than a single bond found in butane. c. It has a higher heat of hydrogenation that butane. d. Electron density is shared throughout the molecule. e. All of the above are true.
8. Which of the following will decarboxylate upon heating?
I II III IV
a. III, IV b. I, III c. Only I d. II, III e. I, IV
9. What would be the product of the following reaction?
H+ +
a. Alcohol b. Carboxylic Acid c. Anhydride d. Ester e. Ether
10. Which of the following is not a suitable method for preparing butanoic acid?
+ a. CH3CH2CH2OH + CO; H3O , heat + b. CH3CH2CH2MgBr + CO2; H3O
+ c. CH3CH2CH2Br + NaCN; H3O , heat - + d. CH3CH2CH2CO2CH2CH3 + HO , H2O; H3O e. CH3CH2CH2CH2OH + H2CrO4
11. In the malonic ester synthesis the enolate can attack the alkyl halide. What type of mechanism is this? a. E2 b. E1 c. SN2 d. SN1 e. No correct answer is given.
12. Which of the following dienes would not react with a dienophile in a Diels Alder reaction?
I II III IV
a. I b. I, II, III c. I, III, IV d. I, III e. II, III, IV
13. Choose the compound that would absorb light of the longest wavelength.
a. b. c. d.
e.
14. Choose the statement that is false regarding Diels-Alder reactions. a. The Diels-Alder reaction is concerted. b. The Diels-Alder reaction forms six-membered rings. c. The Diels-Alder reaction is stereospecific. d. Overall, two new C-C single bonds are formed and two C=C double bonds disappear. e. The exo product is favored in bicyclic Diels-Alder products.
15. Which statement correctly explains why the 1,4-addition product is more stable than the 1,2-addition product in reaction of HBr with 1,3-butadiene? a. The 1,4-product has less steric strain. b. The double bond in the 1,4-product is more substituted than the double bond in the 1,2-product. c. The 1,4-product is less acidic. d. The 1,4-product is resonance stabilized. e. No correct answer given.
Problems
16. Give the Structure for compounds A-E. (15 pts)
+ NaCN Excess H SOCl2 CH3OH 1.DIBALH, toluene, cold A B C D E + + ethanol H2O, heat ether H 2. H2O, H
17. Complete the following synthesis using any additional inorganic or organic compounds necessary. All intermediate products, reagents, and solvents must be shown in order to receive full credit. (10 pts)
18. Complete the following reactions. Indicate stereochemistry is appropriate. (30 pts)
NaBH4
ethanol
1.LiAlH4 , ether
+ 2.H2O, H
1.LiAlH4 , ether
+ 2.H2O, H
1.DIBALH, toluene, cold
+ 2. H2O, H
1.LiAlH4 , ether
+ 2.H2O, H
1.excess CH3MgBr, ether
+ 2.H2O, H
1.(CH3)2CuLi, ether, cold
+ 2.H2O, H
CH3OH
H+, heat
heat
+
19. Mechanism (15 pts)
1 mol HBr
+
a) Provide a mechanism that accounts for the formation of the products in this reaction. All intermediates must be shown, and all electron flow indicated by arrows in order to receive full credit. b) Identify the 1,2 product and the 1,4 product. c) Indicate which product is the kinetic product and which is the thermodynamic product. Briefly explain your choices.