Development of Catalytic Enantioselective Reactions via Palladium Enolates as Key Intermediates

Abstract

Abstract This article describes the catalytic reactions that involve the generation of chiral palladium enolates and their reaction with various electrophiles. Two methods to generate the chiral enolates were developed using the two types of novel chiral palladium complexes: Pd aqua complexes and binuclear Pd μ-hydroxo complexes. In these processes, aqua or hydroxo ligand on palladium metal plays an important role as a nucleophile to promote the transmetallation or as a Brønsted base to abstract an acidic α-proton of the carbonyl group. Using the chiral Pd enolates as key intermediates, a highly enantioselective, catalytic aldol reaction, a Mannich-type reaction, a Michael reaction, and a fluorination reaction were developed.