Bora‐alkenes: Metal Coordination and Reactions with BH‐boranes

Abstract The neutral N‐heterocyclic carbene stabilized bora‐alkene 1 , conveniently prepared by a BH borenium/hydroboration route, forms stable copper, gold or palladium π‐complexes. The polar bora‐alkene B=C system undergoes regioselective hydroboration reactions with the (C 6 F 5 ) 2 BH or C 6 F 5 BH 2 ⋅ SMe 2 boranes. The latter reaction involves a subsequent rearrangement that leads to internal hydride vs. isothiocyanate substituent exchange at the borane pair.