Flash Communication: Siloxides Promote the Iron-Catalyzed Borylation of Aryl Chlorides

Abstract

In contrast to alkoxide salts, siloxide salts MOSiR3 (M = Na, Li) can be used to good effect as activators for B2pin2 in the iron-catalyzed borylation of aryl chloride substrates, in many cases giving results comparable to or better than those obtained previously with highly pyrophoric tBuLi acting as an activator. Preliminary mechanistic investigations reveal a protracted induction period, most likely associated with precatalyst reduction, and these also suggest that the NaOSitBuMe-activated B2pin2 is not as reducing as the equivalent tBuLi-activated species.