Yamaguchi Esterification

Abstract

The regioselective synthesis of highly functionalized esters from carboxylic acids and alcohols using 2,4,6‐trichlorobenzoyl chloride as the condensation reagent in the presence of a stoichiometric amount of 4‐ N , N ‐dimethylamino pyridine (DMAP) is generally known as the Yamaguchi esterification, and 2,4,6‐trichlorobenzoyl chloride is referred to as the Yamaguchi reagent. This reaction is generally carried out by the formation of a mixed anhydride between a carboxylic acid and the Yamaguchi reagent in the presence of Et 3 N. Due to the high reactivity of the mixed anhydride, which is thermally unstable, different results might be obtained at various temperatures as well as with a different order of mixing reactants. This reaction has been modified to take place in a manner of one‐pot reaction. In addition, the esterification of alcohols making use of aromatic anhydride in the presence of Lewis acids or the combination of aromatic anhydride and DMAP have been developed. This reaction has been used in the synthesis of esters and large‐sized lactones.