Periphery-Arranged Bulky Phosphite Ligands: Synthesis and Steric Effect in Cu-Catalyzed Hydrosilylation of Ketones

A series of periphery-arranged bulky phosphites were synthesized, characterized, and applied as a ligand for the Cu-catalyzed hydrosilylation of ketones. These bulky phosphite ligands are highly efficient compared with conventional phosphite ligands. The bulkiness of the phosphite at the periphery works effectively by suppressing aggregation of the active copper species. The origin of the steric effect and reaction mechanism is discussed based on kinetic studies and density functional theory (DFT) calculations.