Gold-Catalyzed Silyl-Migrative Cyclization of Homopropargylic Alcohols Enabled by Bifunctional Biphenyl-2-ylphosphine and DFT Studies

The development of novel ligands specifically tailored for homogeneous gold catalysis permits the development of new gold catalysis. In this work, we report that a remotely functionalized biphenyl-2-ylphosphine ligand enables gold-catalyzed cyclization of homopropargylic alcohols accompanied by an unusual silyl migration, which provides efficient access to 3-silyl-4,5-dihydrofurans. DFT studies of the mechanism of this novel transformation suggest the synergy between the steric bulk of the ligand and its properly positioned remote tertiary amino group in facilitating a concerted silyl migration and cyclative C–O bond formation step.