Abstract
Organoboron compounds exhibit unique properties and valuable applications in organic synthesis, catalysis, materials science, and drug discovery, driving researchers to improve their structural and functional diversity. Despite significant advancements, challenges remain in accessing complex organoboron compounds, particularly in constructing boron-stereogenic skeletons. Here we report a nickel catalyzed diastereoselective hydroboration of olefins using a newly developed vinylborane reagent, CH(2)[double bond, length as m-dash]CH-BH(2)L (where L is a dative donor). This protocol enables the efficient synthesis of versatile vinylborane derivatives featuring a boron-stereogenic center. Mechanistic studies, including the isolation and structural characterization of a key B-H-Ni bonded intermediate, control experiments, and DFT calculations reveal a σ-coordination enabled B(sp(3))-H activation. The σ-coordination induces an oxidative metalation, simultaneously forming B-Ni, C-Ni and C-H bonds. The C[double bond, length as m-dash]C unit in the vinylborane reagent plays a pivotal role in facilitating the otherwise challenging oxidative metalation of the B(sp(3))-H bond. This unique B(sp(3))-H metalation mode may have broader implications for achieving other forms of selective B-H functionalization.