Silylations of Arenes with Hydrosilanes: From Transition-Metal-Catalyzed C¢X Bond Cleavage to Environmentally Benign Transition-Metal-Free C¢H Bond Activation

The construction of carbon-silicon bonds is highlighted as an exciting achievement in the field of organosilicon chemistry and green chemistry. Recent developments in this area will enable the sustainable chemical conversion of silicon resources into synthetically useful compounds. Especially, the catalytic silylation through C¢H bond activation without directing groups and hydrogen acceptors is one of the most challenging topics in organic chemistry and green chemistry. These remarkable findings on catalytic silylation can pave the way to a more environmentally benign utilization of earth-abundant silicon-based resources in synthetic chemistry.

Iridium-catalyzed regioselective silylation of aromatic and benzylic C-H bonds directed by a secondary amine

Reported herein is an iridium-catalyzed, regioselective silylation of the aromatic C-H bonds of benzylamines and the benzylic C-H bonds of 2,N-dialkylanilines. In this process, (hydrido)silyl amines, generated in situ by dehydrogenative coupling of benzylamine or aniline with diethylsilane, undergo selective silylation at the C-H bond γ to the amino group. The products of this silylation are suitable for subsequent oxidation, halogenation, and cross-coupling reactions to deliver benzylamine and arylamine derivatives.