Organic Chemistry Essay

M O D U L E

5 ORGANIC CHEMISTRY: FUNCTIONAL GROUPS
O2.1 Functional Groups O2.2 Oxidation–Reduction Reactions O2.3 Alkyl Halides O2.4 Alcohols and Ethers O2.5 Aldehydes and Ketones O2.6 Reactions at the Carbonyl Group O2.7 Carboxylic Acids and Carboxylate Ions O2.8 Esters O2.9 Amines, Alkaloids, and Amides O2.10 Grignard Reagents Chemistry in the World Around Us: The Chemistry of Garlic

O2.1 FUNCTIONAL GROUPS
Bromine reacts with 2-butene to form 2,3-dibromobutane. Br A CH3CHCHCH3 A Br

CH3 CHP CHCH3

Br2

It also reacts with 3-methyl-2-pentene to form 2,3-dibromopentane. CH3 A CH3 CHPCCH2CH3 Br CH3 A A CH3CHCCH2CH3 A Br

Br2

Instead of trying to memorize both equations, we can build a general rule that bromine reacts with compounds that contain a CPC double bond to give the product expected from addition across the double bond. This approach to understanding the chemistry of organic compounds presumes that certain atoms or groups of atoms known as functional groups give these compounds their characteristic properties.
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FUNCTIONAL GROUP CHEMISTRY

Functional groups focus attention on the important aspects of the structure of a molecule. We don’t have to worry about the differences between the structures of 1-butene and 2-methyl-2-hexene, for example, when the compounds react with hydrogen bromide. We can focus on the fact that both compounds are alkenes that add HBr across the CPC double bond in the direction predicted by Markovnikov’s rule, introduced in Section O1.8. CH2 P CHCH2CH3 CH3 A CH3C PCHCH2CH2CH3 HBr CH3CHCH2CH3 A Br CH3 A CH3C CH2CH2CH2CH3 A Br

HBr

Some common functional groups are given in Table O2.1.
TABLE 02.1 Common Functional Groups Functional Group A OCO A CP C Cq C F, Cl, Br, or I OOH OOO ONH2 Name Alkane Alkene Alkyne Alkyl halide Alcohol Ether Amine Example CH3CH2CH3 (propane) CH3CHPCH2 (propene) CH3C q CH