Carboxylic acids, from alkyls

Strategy We ve seen two methods for preparing carboxylic acids from alkyl halides ... 

Many other examples of synthetic equivalent groups have been developed. For example, in Chapter 6 we discussed the use of diene and dienophiles with masked functionality in the Diels-Alder reaction. It should be recognized that there is no absolute difference between what is termed a reagent and a synthetic equivalent group. For example, we think of potassium cyanide as a reagent, but the cyanide ion is a nucleophilic equivalent of a carboxy group. This reactivity is evident in the classical preparation of carboxylic acids from alkyl halides via nitrile intermediates. 

Formation of carboxylic acid from alkyl halide using the hydrolysis of a nitrile. 

Section 20 Carboxylic Acids from Alkyls, Methylenes and Aryl... 

SECTION 20 CARBOXYLIC ACIDS FROM ALKYLS, METHYLENES AND ARYLS... 

Reactions in which a hydrogen is replaced by carboxyl or a carboxyl containing chain, e.g. RH —RCOOH or RCH2COOH (R=alkyl, vinyl or aryl), are included in this section. For reactions in which alkyl or aryl groups are oxidized to carboxyl, e.g. RCH3 — RCOOH, see section 20 (Carboxylic Acids from Alkyls, Methylenes and Aryls)... 

The conversion Ar-Alkyl — ArH may also be achieved via intermediate carboxylic acids ArCOOH. See section 20 (Carboxylic Acids from Alkyls and Aryls) and section 152 (Hydrides from Carboxylic Acids)... 

The terms hydrides, alkyls, and aryls classify compounds containing reacting hydrogens, alkyl groups, and aryl groups, respectively for example, RCHj-H - RCHjCOOH (carboxylic acids from hydrides), RMe -> RCOOH (carboxylic acids from alkyls), RPh RCOOH (carboxylic acids from aryls). Note the distinction between R CO — RjCHj (methylenes from ketones) and RCOR RH (hydrides from ketones). 

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