Iridium-Catalyzed C-C Coupling of a Simple Propargyl Ether with Primary Alcohols: Enantioselective Homoaldol Addition via Redox-Triggered (Z)-Siloxyallylation

A chiral iridium complex formed in situ from [Ir(cod)Cl](2) and (R)-H-8-BINAP is found to catalyze the direct enantioselective C C coupling of a simple propargyl ether, TIPSOCH2C CH, with primary alcohols to form gamma-hydroxy (Z)-enol silanes with uniformly high enantioselectivity and complete alkene (Z)-stereo-selectivity. As corroborated by deuterium labeling studies, these studies represent the first examples of 1,2-hydride shift-enabled pi-allyl formation in the context of iridium catalysis.