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CHEM 102 [INTRODUCTION TO ORGANIC ]

CHEM 102

Introduction to Organic Chemistry

Exam 1 Material Only

Professor Kelly Boebinger Crafton Hills College

1 Copyright © 2015 Kelly Boebinger | Crafton Hills College

CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Table of Contents:

Lecture Notes: Page Exam 1 Topics: 1 OCHEM Introduction, , , , Exam 2 Topics: 32 , Aromatics, , Phenols Exam 3 Topics: 53 , , Sulfides, Exam 4 Topics: 67 , , Carbonyl Groups Final Exam Topics: All above plus: 86 Amino acids, Proteins

Experiments:

1 Melting Point 97 2 Distillation 101 3 Molecular Models 105 4 Electrophilic Aromatic Substitution 111 5 The Hydroxyl Group 113 6 117 7 Extraction and Isolation of Caffeine 121 8 and Reactions 123 9 Soaps and Detergents 127 10 Milk Protein & Amino Acids 131

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Section 1: Alkanes, Cycloalkanes, Alkenes, Alkynes

What is Organic Chemistry? Organic Chemistry: The study of compounds that contain . There are millions of organic compounds. is the study of all the other elements.

Organic Chemists are interested in the 1) Structure of carbon containing compounds. 2) Nomenclature (naming) of organic compounds. 3) Physical properties of organic compounds. 4) Synthesis of organic compounds. 5) Reactions of organic compounds.

Structure of Organic Compounds: The : contain a small, dense nucleus surrounded by . The nucleus is positively charged and contains most of the mass of the atom. The nucleus contains protons, which are positively charged, and neutrons, which are neutral. The atomic number of an element is equal to the number of protons in the nucleus. The atomic weight is approximately equal to the sum of the number of the protons and neutrons in the nucleus. Electrons are concentrated in certain regions of space outside the nucleus called orbitals. The orbitals, which differ in shape, are designated by the letters s, p, d, and f. There are one s orbital, three p orbitals, five d orbitals, and seven f orbitals. Each orbital can hold two electrons maximum.

BONDS: Ionic, Covalent, Multiple, Polar Covalent Ionic bonds: are formed by the transfer of one or more valence electrons from one atom to another. Because electrons are negatively charged, the atom that gives up the electrons becomes positively charged, a cation. The atom that receives the becomes negatively charged, and an anion. The atoms are held together by electrostatic force.

Electropositive (+): atoms that tend to give up electrons, such as . Electronegative (-): atoms that tend to accept electrons, such as .

Carbon is neither strongly electropositive nor strongly electronegative.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Covalent bonds: are formed by the sharing of electron pairs. When two or more atoms are joined by covalent bonds it is known as a .

Carbon is tetravalent (four valence electrons): Carbon always has four bonds, (eight electrons) around it to fulfill the octet rule. These bonds are covalent. The unique property of carbon atoms is the ability to share electrons not only with different elements but also with other carbon atoms, and form multiple bonds.

Multiple Bonds in Organic Compounds Carbon can form multiple bonds with a neighboring carbon. Atoms may sometimes share more than one electron pair and form multiple bonds. A shares two electron pairs (4 electrons) and a shares three electron pairs (6 electrons). Single Bond Double Bond Triple Bond

Organic Compounds and Polar Covalent Bonds Polar : a covalent bond in which the electron pair is not shared equally between the two atoms. This occurs when there's a difference in electronegativity between the atoms. The atoms that are linked carry a partial negative and partial positive charge.

 = delta = polarity Dipole moment = μ

CH3Cl chloromethane or methyl chloride (a substituted ) The electronegative chloride removes electron density from carbon, leaving it electropositive.

Elements Found in Organic Compounds Other Than Carbon 1. : almost all compounds 2. : Cl, Br, ( also I & F , but are less common) 3. oxygen: alcohols, ethers, ketones, , and aldehydes 4. sulfur: thiols and 5. nitrogen: amines, , amino acids

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Hydrocarbon: Contains only hydrogen and carbon

Hydrocarbon Alkane

Bonding

General Formula Saturated or

Unsaturated

Example

Structure

Name Geometry

Bond Angle

Hybridization

Hybridization: Hybrid of s and p orbitals to form bonds. Hybridization can be determined on any atom that is bonded to 2 or more other atoms; sp, sp2, sp3

H H H H H C C H C C H H H H H H

H C O

C C CH C C H H C C H 2

H CH 3

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Ways to represent an :

Molecular Formula: Only shows the ratio of atoms relative to each other, does not explain how atoms are connected together. For example C6H14

Structural Formulas: The most common structural formula used is a condensed structural formula, and many times simply referred to as a structural formula, omitting the word condensed. In some cases and expanded structural formula is used to emphasize features on a molecule.

Expanded Structural Formula shows in two dimensions, all of the atoms in a molecule and all of the bonds connecting them. Many times this is described as showing all bonds explicitly.

Condensed Structural Formula uses groupings of atoms, in which the central atoms and the atoms connected to them are written as a group, to convey molecular structural information.

Line or Skeletal Structures: Perhaps the ultimate abbreviated structures are the use of lines to represent the carbon framework. Carbon at bend or end (also intersection). Often used to represent rings of .

Molecular CH4 C3H8 C6H14 Formula Expanded Structural Formula

Condensed Structural Formula

Examples of Line Structures

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Structure of straight chain carbons: When a number of carbon atoms are connected together, they are said to be in a straight chain, even though in the actual molecule, the carbon atoms are in a zigzag pattern.

Once you are aware of these dimensional structures of , you do not have to explicitly show this in most cases.

Three dimensional shapes of carbon compounds. Carbons at intersections. MAKE MODELS

out of plane “”””” behind plane ____ in plane Solid Wedge Dashed Wedge

ALKANES: are hydrocarbon molecules of carbon and hydrogen that have only single bonds.

General formula for an Alkane: The formula for an alkane is CnH2n+2 where n is equal to the number of carbon atoms. Example: For an alkane, which contains five carbons. n = 5 2n + 2 = 2(5) + 2 = 12 The molecular formula is thus C5H12. This corresponds to .

Molecular Formula Name Number of Prefix Carbon atoms

CH4 1 meth- C2H6 2 eth- C3H8 3 prop- C4H10 4 but- C5H12 pentane 5 pent- C6H14 6 hex- C7H16 7 hept- C8H18 8 oct- C9H20 9 non- C10H22 10 dec-

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Alkanes can be shown in the following way, keeping in mind that they are three- dimensional. The following represents the structures that are only straight chain, and do not include any branched alkanes which will be covered later.

Draw the condensed structural formula for the following: methane hexane

ethane heptane

propane octane

butane nonane

pentane decane

Conformations of Alkanes: Conformations are differing orientations of a molecule made possible by rotations around a single bond. Rotation about carbon-carbon single bonds is an important property of alkane molecules.

As a result of rotation around single bonds, alkane molecules (except methane) can exist in infinite numbers of orientations, or conformations. Different conformations for C4H10

Problem: Predict if the following are of each other or different conformations. CH3 CH CH a. CH2 and 3 3 CH2 CH2 CH2 CH2 CH2 CH3

CH3 CH3 b. CH3 CH CH 2 CH 3 and CH3 CH2 CH2 CH2

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Structure of branched chain alkanes and Isomers:

• If an alkane contains four or more carbon atoms, there can be branched alkanes. • Structural isomers are compounds with the same molecular formula but a different structural formula (different connections between atoms).

The number of structures possible = number of isomers

IUPAC system is the first name listed; it is the most current way to name compounds. The older way to name is still sometimes used, so it is necessary to know some of the old names. (Old way to name: n- meant straight chain or on carbon 1, and iso meant something is coming off carbon 2)

C H has the following structural formulas: 2 structures = 2 isomers 4 10 butane (n-butane) 2-methylpropane ()

C H has the following structural formulas: 3 structures = 3 isomers 5 12 pentane 2-methylbutane 2,2-dimethylpropane

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

C6H14 has the following structural formulas: 5 structures = 5 isomers hexane 2-methylpentane

3-methylpentane 2,2-dimethylbutane 2,3-dimethylbutane

As the number of carbon atoms increase the number of possible isomers increase exponentially. Branched alkanes and the number of isomers: C7H16 9 isomers C8H18 18 isomers C9H20 35 isomers C10H22 75 isomers C20H24 366,319 isomers C30H26 4,111,846,763 isomers C40H28 62,491,178,805,831 isomers

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Alkyl groups, which are attached to a carbon chain, are derived from the respective alkane.

Alkane Group Structure

methane methyl

ethane ethyl

n-propyl propane 1-propyl

propane Isopropyl 2-propyl

butane n-butyl 1-butyl

butane sec-butyl 2-butyl tertiary butyl 2-methyl propane tert-butyl t-butyl

2-methyl propane isobutyl

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Nomenclature of Alkanes (IUPAC) A. Name the main chain, the longest continuous chain of carbons. This is the parent chain. Number the carbon atoms in the main chain that will give the lowest composite number for the (s). B. Identify and number the branching substituent(s). C. Write the name as a single word.

Numbers,numbers Example 1: are separated by commas 2,3 A. a pentane B. 2-methyl substituent Numbers-letters are C. 2-methylpentane separated by dashes 3-methylF = fluoro, Cl = chloro, Br = bromo, I = iodo Example 2: When two or more different A. a hexane , list them alphabetically B. 3-ethyl and 3-chloro substituent C. 3-chloro-3-ethylhexane

Number from the Example 3: end which will give the lowest composite A. an octane number for the substituents B. 3-methyl and 5-ethyl substituent When two or more C. 5-ethyl-3-methyloctane

When there is a tie Example 4: from each direction, break the tie A. a heptane alphabetically. B. 5-methyl and 3-ethyl substituent When two or more C. 3-ethyl-5-methylheptane

If more than one of the same substituent, use prefixes di, tri, tetra, etc. (These prefixes are NOT used to alphabetize.) You must put the address of each substituent, even if they are the same. 3,3-dimethyl…..

Example 5: Name the following structure

CH2 CH3

H 3C CH CH2 CH2 CH2 CH(CH3)2

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Problems: Give the IUPAC name for each of the following: a. CH3 CH 2 CH 2 CH CH3 a.

CH3 b. C H3 CH CH CH2 CH C H3 b. CH 2 CH3 CH3

CH3 CH3 c. C H3 CH C CH2 CH3 c.

CH CH 3 2 CH3 d. CH3 CH CH CH CH2 CH3 d.

CH CH3 3 CH2

CH3 e. CH2 CH 2 CH CH2 CH2 e. CH CH 3 CH2 3

CH2

CH3 f. CH3 (CH 2)8 CH 3 f.

Br g. H3C CH 3 g.

Cl Draw the condensed structural formula for each of the following: a. 2-methylbutane a.

b. 3,4-dimethylhexane b. c. 3-ethyl-3-methylpentane c.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

d. 2,3,4,5-tetrabromoheptane d.

e. 3,5-diethyloctane e.

f. 4-propylnonane f.

Types of carbons encountered in alkanes Primary (1o) Secondary (2 o) One R group (3 ) Two R groups (2 hydrogens)

Tertiary (3 o) Quaternary (4 o) R can be written with tick marks or numbers to indicate that R can be Three R groups (1 hydrogen) Four R groups (no hydrogens) the same or different from each other

o R is a generalization for any group. Thus R can be CH3-, CH3CH2-, etc. The R groups in the 2 , 3o, 4o cases can be the same or different.

Multiple bonds, each bond is counted as an R group, for example:

H3C CH CH CH3

3 R groups, 3

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Examples of carbon types:

Circle the Primary Carbons

CH3CH3 CH3CH2CH3

Circle the Secondary Carbons

CH3CH2CH3 CH3CH2CH2CH3

Circle the Tertiary Carbons

CH3 CH CH CH2 CH CH3

CH CH3 CH3

CH2

Circle the Quaternary Carbons

CH3

CH3 CH C C CH

CH 3 CH2 CH3

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Properties of Alkanes

Physical Properties of Organic Compounds and How They Differ from Inorganic Compounds.

Organic Inorganic Bonds Covalent Ionic Solubility Not water soluble. Usually water Exceptions: Compound with small number soluble of carbons and polar or contains OH group. Melting Point Low M.P., thus gases, liquids & low melting Liquids and high solids like waxes melting solids. Some gases like NH3

. The first four alkanes: methane, ethane, propane and butane are gases at room temperature. . Alkanes with five to fifteen carbons are liquids at room temperature. . Alkanes with sixteen or more carbons are waxes with low melting points. . Odorless, colorless, tasteless. . Nonpolar and are insoluble in water, but soluble in nonpolar solvents. . Less dense than water. . Flammable. . Increase in melting and with increasing molecular weight. Branching tends to decrease melting and boiling point. . Low reactivity.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Reactions of Alkanes: Alkanes tend to be fairly unreactive; two major reactions will be covered.

1. Combustion Reactions (Oxidation). These are reactions when a substance is burned. These are easier to balance when you use molecular formulas.

CH4 + 2 O2  CO2 + 2 H2O + energy

2 C6H14 + 19 O2  12 CO2 + 14 H2O + energy

Problems: Write the balanced combustion reaction of propane.

Write the combustion reaction for butane.

2. Reactions of Alkanes (requires heat or light as a catalyst): Halogenation: is involved in the reaction. Substitution Reaction: An atom takes the place of another atom on a carbon. These reactions are to be written using condensed structural formulas. (Only 1 halogen can substitute at a time)

R-H + X2 Heat or Light R-X + H-X Alkane Halogen  or λ Halogenated alkane

Problems: Write the bromination reaction of ethane.

Write the chlorination reaction of propane.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Cycloalkanes (Unsaturated CnH2n) Carbon atoms can form cyclic (ring) compounds when there are 3 or more carbons. These compounds have the same number of carbons, but two less hydrogens than the corresponding open chain alkanes. Thus they are not isomers with the linear or branched alkanes with the same number of carbons.

Cyclopropane and are more reactive than the corresponding alkane. This is due to the distortion of bond angles from the 109.5o (). You can see from the models of these compounds that the rings are fairly rigid. The carbon-carbon bonds cannot be rotated, or even move relative to one another, until you get to larger rings consisting of five or more carbon atoms.

cyclobutane

H H H H H H C C C C C H C C H H H H H H H

H H CH2 H H H2C CH2 H H

H H H2C CH2 H H CH2

Cyclohexane and its conformations Newman projection

The Chair conformation of cyclohexane H H H H H H H H H H H H

The Boat conformation of cyclohexane H H H H H H H H H H

H H

For cyclohexane, there is considerable amount of steric and torsional strain in the boat form. The cyclohexane molecule prefers to be in the chair conformation. Chair Boat

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Nomenclature of Ring Compounds For monosubstituted rings: Name the substituent first, then the parent compound (Don’t forget cyclo), write as one word.

For polysubstituted rings: Use the following IUPAC nomenclature. A. Number in the direction (clockwise or counter clockwise), which will give the lowest composite number for the substituents. B. If there is a tie with the composite numbers, start with the substituent (group), which has alphabetical priority it will be on carbon 1. C. List substituents alphabetically, then the parent name. (Don’t forget cyclo), write as one word. 1,4-dimethylcyclohexane 1-ethyl-2-methylcyclohexane

1,1,3-trifluorocyclohexane 1-ethyl-3,5-dimethylcycloheptane

1-t-butyl-3-isopropylcyclohexane 1,1-dibromocyclopentane

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Biochemical Interest: Various uses of some alkane and compounds

Cyclopropane is used as an anesthetic. It is usually mixed with helium as it tends to form explosive mixtures when mixed with oxygen.

1-bromo-1-chloro-2,2,2-trifluoroethane (IUPAC) Halothane (fluothane) is used as an anesthetic. Used in Dentistry

Chloroethane (ethyl chloride) is used as a local anesthetic as it cools the skin upon evaporation.

Carbon tetrachloride (tetrachloromethane) was once used as a general anesthetic until it was found to cause liver damage.

Hexachlorocyclohexane (IUPAC) 1,2,3,4,5,6-hexachlorocyclohexane (Lindane) is used to kill mites and lice, which are known to infect humans. This compound must be used with caution as it is fat soluble and nonbiodegradable.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Alkenes and Alkynes (Unsaturated Hydrocarbons)

A comparison of single (σ) , double (σ, π) & triple (σ, 2π) Bonds:

The bond that holds two atoms together and the first bond that forms is a (σ), this is present in all covalent bonds including alkanes, alkenes and alkynes. For ethane, there is a sigma bond between carbon and carbon and also a sigma bond between carbon and hydrogen.

When multiple bonds are present, each multiple bond starts with a sigma bond, and then the pi (π) bonds form next. For ethane (double bond), there is both a sigma bond and a pi between carbon and carbon, and only a sigma bond between carbon and hydrogen. For ethyne, (triple bond), there is a sigma and two pi bonds between carbon and carbon, and a sigma bond between carbon and hydrogen.

Molecular orbital Pictures:

H H H H H C C H Ethane (Alkane) C C Ethene (Alkene) H H H H

HC CH Ethyne (Alkyne)

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Nomenclature of Alkene and Alkyne compounds: Double (alkene) and triple (alkyne) bonds need to be included in the name of the compound. ethene ethyne

When a multiple bond is in a compound with 4 or more carbon atoms, a numbering system is used to identify the location of the multiple bond for clarification. 1- 2-butene

1- 2-butyne

Naming Alkenes & Alkynes

1. Locate the multiple bond. The longest chain must include the entire multiple bond, this is the parent name. Alkenes have an –ene ending, alkynes have an – yne ending 2. Locate the position of the multiple bond in the main chain. Give it the lowest possible number from either direction. 3. Identify and number the substituents in the main chain. List in name alphabetically. 4. The name is written as one word.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Give the IUPAC name or the structure for the following:

CH3

H3C CH C CH CH3 H3C C C CH(CH3)2

CH3

3-ethyl-1,4-pentadiene 3-methyl-1-butyne

3,6-diethyl-1,4-cyclohexadiene

H CH3 C

CH3 CH2 CH2 C CH2 CH3

cyclohexyne 1,3-

3-methylcyclopentene

H3C CH 3

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Structure of Alkenes: With alkanes there is free rotation around the carbon-carbon single bond. With alkenes, the double bond between the carbon centers prevents rotation. Thus the geometry is fixed at the carbon-carbon double bond. This gives the possible cis and trans geometrical isomers as the double bond defines the relationship. The R groups do not have to be the same.

Cis Trans Terminal (not cis nor trans)

Alkene isomers of C4H8

1-butene cis-2-butene trans-2-butene 2-methylpropene

Some alkene isomers of C5H10

1- cis-2-pentene trans-2-pentene

Some alkene isomers of C6H12

1- cis-2-hexene trans-3-hexene

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Give the structure for the following: cis-1-bromo-2-chloroethene trans-4-propyl-2-

trans-1-fluoropropene cis-2-iodo-3-hexene

Cyclic molecules can also have cis or trans features. Name the following:

H Br H Cl

Br

CH3 H H

Properties of Alkene & Alkyne Molecules

1. Nonpolar: soluble in nonpolar solvents, insoluble in water, and less dense than water. 2. Chemically reactive, and alkynes are generally more reactive than alkenes with most reactions being addition reactions. Flammable. 3. FOR ALKENES:  Melting points and boiling points are similar to alkanes with the same number of carbons. Cis isomers have higher melting point and boiling point than the corresponding trans .  Slight odor for low molecular weight terminal alkenes.  May display cis-trans relationships about the double bonds.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Reactions of Alkene & Alkyne Molecules

Combustion reactions: Covered in alkane section. All carbon compounds can undergo combustion such as alkane, alkene, alkyne, cyclic compounds etc.

Addition Reactions: are typical of alkenes and alkynes. An may be visualized as a process by which the double or triple bonds are fully or partially broken in order to accommodate additional atoms or groups of atoms in the molecule.

1. Addition Reaction for Alkene & Alkyne Molecules Hydrogen atoms add across the multiple bond to yield the 1,2-addition product. Alkenes and alkynes undergo hydrogenation reactions in the presence of , , or to give the corresponding alkane. H H Pt, Pd, or Ni C C H2 C C +

an alkene an alkane

Problem: Write the hydrogenation reaction of 2-pentene, name the product.

Problem: Complete the reaction, name the product.

CH3 CH3 Pt H

+ H2 H

Alkyne (Triple bond) requires 2 hydrogen molecules to form an alkane. H H Pt, Pd, or Ni C C + 2H2 C C

H H

Problem: Write the hydrogenation reaction of propyne.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

2. ALKENE: Halogenation Addition Reaction : Halogens add across a double bond to yield the 1,2-dihalo addition product. (This course will not cover alkyne halogenation reactions)

H H

H H + CCl 4 C C X2 H C C H H H X = Br, Cl, rarely I or F X X CCl4: carbon tetrachloride is a reaction solvent and is not involved in the addition reaction.

Problem: Write the bromination reaction of 2-methylpropene.

Keep in mind addition reactions can also occur even if the double bond is in a ring.

+ +

trans cis 100% 0% Why the huge difference in the amounts of each product?

Steric hindrance (effect): (Something is physically in the way) occurs when groups within a molecule are in the way by its physical presence and prevents other molecules from bonding or reacting.

 In the case of the above reactions, there isn’t enough room for both halogen atoms to add to the same side of the molecule. As a result of this, the trans product is produced to the exclusion of the cis product on the ring. This reaction undergoes anti-addition.  Anti-addition: one atom attaches to the top of the double bond and the second atom attaches to the bottom.  Syn-addition: the atoms bond to same side of the double bond.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

3. ALKENE: : hydrogen and halogen add across a double bond (This course will not cover alkyne hydrohalogenation reactions) H H

H H + C C HX H C C H

H H X = Br, Cl H X

For unsubstituted alkenes or for symmetrically substituted alkenes:

H H

C C + HBr H H ------

H3C CH3 C C + HBr

H3C CH3

For unsymmetrical alkenes addition of HCl or HBr occurs with Regiochemistry, the preference for the formation of one product over another.

H3C H

C C + HBr

H 3C H 100 % 0 % ------

H3C CH3

C C + HBr

H3C H mostly this very little

Markovnikov Rule predicts the regiochemistry of HX addition to unsymmetrically substituted alkenes.

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

Markovnikov’s Rule: The addition of H-X across a double bond proceeds in such a manner that the hydrogen will attach to the carbon so the most stable is formed. The hydrogen (H+) attaches first by attacking the double bond (electron rich, negative region), attaching to the carbon with the more hydrogens, to leaving the most stable carbocation (+). The halogen (X-) is attracted to the positive charge of the carbocation and adds second. A more simplistic viewpoint, (not the definition) is that hydrogen will attach to the carbon with the most hydrogen atoms directly attached.

Carbocation Stability: Listed most stable R3C+ to least stable H3C+

Tertiary (3o) Secondary (2o) Primary (1o) Methyl very stable moderately unstable very unstable

Mechanisms for addition of HX across the double bond.

X- - H-X H-X X X H H H X H H H3C H3C H C H + C C 3 + H C C C C C C C C C C H3C H C H C H H C H3C 3 3 3 H H H3C H H H3C H H H C H H C 3 H 3 3o carbocation formed, very stable 1o Carbocation, not stable, won’t form

Problem: Write the reaction of HCl with 1-butene, name the product

Complete the reaction CH CH3 3 ether Cl + HCl H

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

4. ALKENE: Hydration of Alkenes: Hydrogen and hydroxide add across a double bond (This course will not cover alkyne hydration reactions)

The hydration of alkenes can be formally viewed as the 1,2-addition of water (H then OH) across a double bond in a Markovnikov fashion.

H R H R H2SO4 C C + HOH H C C R

H R 250 °C H OH

Problem: Write the reaction of 2-methylpropene and HOH.

Biochemical Interest: Various Alkene & Alkyne Compounds

LYCOPENE: (antioxidant) Fruits and vegetables that are high in lycopene include tomatoes, watermelon, pink grapefruit, pink guava, & papaya. Unlike other fruits and vegetables, where nutritional content such as vitamin C is diminished upon cooking, processing of tomatoes increases the concentration of bioavailable lycopene. Lycopene in tomato paste is four times more bioavailable than in fresh tomatoes. For this reason, tomato paste is a preferable source as opposed to raw tomatoes.

β-CAROTENE (Vitamin A) can interact with medication used for lowering .

HO

ICHTHYOTHEREOL (a poison from a plant, has been used as bait to kill fish. Why?) CH

H3C C C C C C C CH O

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CHEM 102 [INTRODUCTION TO ORGANIC CHEMISTRY]

How to study Organic Reactions- Go through all the notes; write reactions together as a study guide. PRACTICE & REWRITE then PRACTICE & REWRITE, as many times as you need. Here are suggestions for formats that have worked well for other students: Do NOT turn this page from these notes in, make your own review sheets!

Reaction name: Combustion – when a carbon compound is burned Reaction type: Oxidation Catalyst: none General reaction: CH4 + 2 O2  CO2 + 2 H2O + energy Example 1: (Write in other examples from notes or your own to help you practice) Example 2: Example 3:

Reaction name: Halogenation of alkanes Reaction type: Substitution Catalyst: Heat or light:  or  General reaction: R-H + X2  R-X + HX Example 1: Example 2: Example 3:

Another suggestion: Make a table, a template is on the Blackboard site for you if you want to use it. See the following example.

Section/Details REACTIONS Alkene H R

H R Hydrohalogenation: + ether Follows Markovinkov C C HX H C C H rule, H to side with H H X = Br, Cl more H’s H X

Note: You will want to bring your template to class to make rings for the

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