Chiral cyclometalated oxazoline gold(III) complex-catalyzed asymmetric carboalkoxylation of alkynes

Abstract

Asymmetric catalysis by using novel chiral O,O′-chelated 4,4′-biphenol cyclometalated oxazoline gold(III) complexes has been developed. A high yield (≤89%) and a high enantioselectivity (≤90% ee) were achieved in asymmetric carboalkoxylation of alkynes. Enantioselectivity could be significantly improved from 19% to 90% ee by increasing the steric size of the substituent on the chiral oxazoline ligand. Catalytically active AuIII species and the origin of chiral induction are proposed.