Mechanistic Insight into the (NHC)copper(I)-Catalyzed Hydrosilylation of Ketones

Abstract

(NHC)­copper­(I) hydride catalyzed ketone hydrosilylation is an efficient method for the enantioselective synthesis of secondary alcohols. Herein, we represent a computational study of this reaction using density functional theory (DFT) on realistic model systems. This study is supported by kinetic investigations, using in situ FTIR measurements. The calculations validate the previously proposed reaction mechanism and explain the high activity of (OR¹)_<i>x</i>R²_3–<i>x</i>Si–H types of silanes. Experimental evidence in favor of the monomeric (NHC)­CuH form of the catalyst is also given. Combining experimental and theoretical results furthermore highlights a Lewis base activation of the hydrosilane, leading to a modified suggestion for the mechanistic scheme of the catalytic cycle