Rh(I)-Catalyzed Regio- and Enantioselective Ring Opening of Vinyl Cyclopropanes
Stephen J. Webster, László B. Balázs, F. Wieland Goetzke, Violeta Stojalnikova, Ke Liu, Kirsten E. Christensen, Harold W. Mackenzie, Stephen P. Fletcher
Abstract
High Resolution Image Download MS PowerPoint Slide We describe a Rh(I) catalyzed asymmetric ring opening of racemic vinyl cyclopropanes using aryl boronic acids as C-nucleophiles. When ferrocene-based chiral bisphosphines are used as ligands, the products are obtained with regioselectivities typically 99:1 r.r. and ee’s generally between 88 and 96%. A wide range of aryl boronic acids can be used, and the products can be converted into a variety of targets. Preliminary mechanistic studies indicate that Zn(OTf) 2 plays a significant role in the reaction by promoting rhodium-ligand complex formation and accelerating the reaction. We expect this method and these mechanistic insights to be useful in the development of new asymmetric methods.