Photo-induced catalyst-free formal carbon insertion of acylsilanes into B–B and B–Si bonds

Abstract

A formal carbon insertion of acylsilanes into B–B and B–Si bonds has been developed. The in situ formed siloxycarbene from acylsilane under blue LED irradiation worked as the intermediate for the reaction. Commercially available B₂(pin)₂ and (pin)B-SiMe₂Ph were employed as cross partners. No base or catalyst was needed. Both aromatic acylsilanes and aliphatic acylsilanes were applicable. The yields were up to 99% and the utility of the product was demonstrated. When 2-furyl and 2-thiophenyl acylsilanes were used, the B(pin) ring was enlarged to a six-membered ring through the siloxy group rearrangement from carbon to boron.