Microwave reactor assisted chiral Brønsted acid catalyzed asymmetric synthesis

Microwave reactors have been used in organic synthesis to facilitate reactions since the 1980s. In this paper we show that the reaction time can be substantially shortened for our previously developed chiral Brønsted acid catalyzed desymmetrization of diesters to yield lactones when performed in the microwave from 72 h to 20 min without loss in yield or enantiopurity. Three additional organocatalyzed asymmetric reactions from current literature were explored and shown to exhibit similar benefits with the use of a microwave reactor. Although not traditionally thought of as a tool in asymmetric organocatalysis, we show that microwave reactors can benefit many enantioselective reactions, particularly those with long reaction times. • Microwave reactor decreases reaction time without loss of yield or enantiopurity. • Four examples using chiral Brønsted acids given. • Procedures easily adapted.