Nucleophilic Substitution Reactions at the Carboxyl Carbon

Abstract

C=O double bonds occur in a series of different classes of compounds: In aldehydes and ketones, which together are referred to as carbonyl compounds, C=O double bonds are part of a carbonyl group, Csp2=O. Carboxylic acids, carboxylic esters, and carboxylic amides, as well as all carboxylic acid derivatives used as acylating agents (see Section 6.3) are termed collectively as carboxyl compounds and are thereby distinguished from the carbonyl compounds. They contain a carboxyl group Csp2(=O)-Het. C=O double bonds are also part of carbonic acid derivatives Het1-Csp2(=O)-Het2. Carbonic acid derivatives contain a carboxyl carbon and a carboxyl oxygen, too. Thus, there is no difference between the nomenclatures for the C=O groups of carbonic acid derivatives and carboxylic acid derivatives. Finally, there are Csp=O double bonds; these occur in ketenes and isocyanates.