B(C6F5)3‐Catalyzed sp3 C—Si Bond Forming Consecutive Reactions

Abstract

Transition metal‐catalyzed hydrosilylation is one of the most widely utilized reduction methods as an alternative to hydrogenation in academia and industry. One feature distinct from hydrogenation would be able to install sp3 C—Si bond(s) onto substrates skeleton via hydrosilylation of alkenes. Recently, B(C6F5)3 with hydrosilanes has been demonstrated to be an efficient, metal‐free catalyst system for the consecutive transformation of heteroatom‐containing substrates accompanied by the formation of sp3 C—Si bond(s), which has not been realized thus far under the transition metal‐catalyzed hydrosilylative conditions. In this review, I outline the B(C6F5)3‐mediated consecutive hydrosilylations of heteroarenes containing quinolines, pyridines, and furans, and of conjugated nitriles/imines to provide a new family of compounds having sp3 C—Si bond(s) with high chemo‐, regio‐ and/or stereoselectivities. The silylative cascade conversion of unactivated N‐aryl piperidines to sila‐N‐heterocycles catalyzed by B(C6F5)3 involving consecutive dehydrogenation, hydrosilylation, and intramolecular C(sp2)—H silylation, is presented in another section. Chemical selectivity and mechanism of the boron catalysis focused on the sp3 C—Si bond formation are highlighted.