キラルなアゾリウム塩による銅触媒不斉共役付加反応

Abstract

The Cu-catalyzed 1,4-addition of organometallic reagents to α,β-unsaturated compounds is a powerful method for the efficient construction of carbon-carbon bonds. In the past decade, catalytic asymmetric conjugate addition reactions with high enantioselectivities have been successfully achieved by using a variety of chiral ligands. Among the growing number of the chiral ligands, N-heterocyclic carbenes (NHCs) have been recognized as useful ligands. One of the most attractive features that make NHCs a very interesting class of ligands is the easy access to their ligand precursors (mostly azolium salts). The azolium salts are very easy to functionalize often by simple reactions that allows the design of a wide variety of NHC ligands and the rapid elaboration of NHC ligand libraries. In this review article, the Cu-catalyzed asymmetric conjugate addition reactions by employing easy accessible and highly tunable functionalized azolium salts are summarized.