Rhodium-Catalyzed Alkene Hydrosilylation via a Hydride Shuttle Process by Diene Ligands: Dramatic Enhancement of Regio- and Diastereoselectivity

A cooperative ligand‐assisted, Rh‐catalyzed intramolecular alkene hydrosilylation of homoallylic silyl ethers (1) was developed to provide 1,3‐trans‐oxasilacyclopentanes (trans‐2) in a highly regio‐ and diastereoselective manner. The modification of metal‐ligand architecture employing an inner‐sphere functional diene ligand (1,3‐cyclohexadiene) and a supporting phosphine ligand (BINAP) was identified as responsible for dramatic enhancement of selectivities. Mechanistic details of a diene ligand‐mediated hydride shuttle process are presented as the potential mechanistic driving force behind the high level of the selectivities. A cooperative functional diene ligand and a supporting phosphine ligand mediated, Rh‐catalyzed intramolecular alkene hydrosilylation of homoallylic silyl ethers was developed to provide 1,3‐trans‐oxasilacyclopentanes in a highly regio‐ and diastereoselective manner. A diene ligand mediated hydride shuttle process is proposed as the mechanistic driving force behind the high level of selectivities.