Preparation and Carbocupration-Silylation of Allyl Propiolates: Vicinal Functionalization To Form Polysubstituted (E)-Vinylic Silanes

The preparation and TMSOTf-mediated catalytic carbocupration-silylation of allylic propiolates has been investigated, expanding on previous syntheses of a variety of beta-alkyl-and beta-aryl-substituted vinylsilanes from an ethyl propiolate precursor. With few exceptions, the series of synthesized O-allyl (E)-vinylsilanes has been isolated in high yields (61-89%) with exceptional diastereoselectivities (E/Z >20:1). Additionally, we demonstrated a novel LDA-initiated, TMSCl-mediated Ireland-Claisen rearrangement of a representative allylic ester.