Ligand-Controlled Site- and Enantioselective Carbene Insertion into Carbon-Silicon Bonds of Benzosilacyclobutanes

We report herein a highly efficient palladium-catalyzed carbene insertion into strained Si-C bonds of benzosilacyclobutanes, which provides an efficient method to access alpha-chiral silanes. With a sterically hindered ligand, carbene insertion into the C(sp(3))-Si bond of benzosilacyclobutanes occurred in excellent site- and enantioselectivity, while C(sp(2))-Si bond insertion occurred selectively with less sterically hindered ligands. Reaction mechanism, in particular the roles of the chiral ligands in controlling the site-selectivity of the insertion reactions, are elucidated by using hybrid density functional theory.

Automated summary

In this study, a highly efficient palladium-catalyzed carbene insertion reaction into strained Si-C bonds of benzosilacyclobutanes was reported, providing an efficient method for accessing alpha-chiral silanes. It was found that with a sterically hindered ligand, the carbene insertion occurred selectively on the C(sp(3))-Si bond of benzosilacyclobutanes with excellent site- and enantioselectivity, while selectively occurred on the C(sp(2))-Si bond with less sterically hindered ligands. The reaction mechanism, particularly the roles of chiral ligands in controlling the site-selectivity of the insertion reactions, was elucidated using hybrid density functional theory.