Enantioselective Rh(I)-Catalyzed Conjugate Alkynylation of 5-Benzylidene Meldrum’s Acid with TMS-acetylene

Abstract

The Rh-catalyzed conjugate addition of TMS-acetylene to alkylidene Meldrum’s acids was developed. Exceptional ee’s and yields were attained using chiral 3,5-Xylyl-BIPHEP ligand. The scope of the reaction was also shown to be very broad with functionalities including phenol, silyl ether, and boronates being tolerated. The successful deprotection and subsequent Sonogashira coupling reaction of the terminal alkyne was also developed.