Unprecedented B―H activation through Pd catalysed B―Cvinyl bond coupling on borane systems

Abstract

A Pd-induced cascade B–Cvinyl coupling that produces multiple B–Cvinyl bonds starting from a single B–I bond has been demonstrated. The process is most probably stimulated by the geometrical disposition of the B–H bonds confronting the B–Pd sites, along with the hydride character of the B–H units. Two and one B–Cvinyl couplings on the metallacarborane substrate have been generally obtained, but formation up to six B–Cvinyl bonds has been observed. A theoretical reaction mechanism involving an unprecedented B–H activation is proposed to interpret the multisubstitution process.