2.1.3 Acyloin, Benzoin, and Related Reactions

Abstract

AbstractThis chapter gives a broad overview of different thiamine diphosphate (ThDP) dependent enzymes and their applicability in organic synthesis as a practical alternative to traditional cross-coupling reactions. Complementary to known nonenzymatic umpolung reactions, enzymatic versions of the benzoin condensation, the asymmetric cross-benzoin condensation, the resolution of racemic 2-hydroxy ketones via C—C bond cleavage, the synthesis of bis(α-hydroxy ketones), the homocoupling of aliphatic aldehydes, the Stetter reaction, and aldehyde–ketone cross-benzoin reactions have been developed. The broad diversity of the products from enzymatic transformations is nicely complemented by the possible subsequent diversity-oriented chemistry. Starting from simple, commercially available aldehydes, many different chiral building blocks can be selectively obtained in a few steps, thus mimicking the diversity-oriented biosynthesis of natural biosynthetic pathways.