Hydroboration is one of the most widely utilized reactions for olefin functionalization and organoboron synthesis. While asymmetric hydroboration is well established for creating homochiral alkanes with stereogenic carbon centers, catalytic hydroboration to incorporate boron stereocenters remains an unresolved challenge. In this work, through the rational design of a nickel/chiral phosphoramidite catalyst system, we report a boron-stereogenic hydroboration of a wide range of unactivated and activated olefins using a prochiral, four-coordinate vinylborane reagent. This reaction enables the construction of enantioenriched B(sp3)-C(sp3) skeletons containing both boron and carbon stereocenters. Experimental and computational studies reveal a unique ligand-to-ligand hydrogen transfer pathway for the activation and metalation of inert B(sp3)-H bonds, providing mechanistic insights into the observed enantioselectivity. With its broad substrate scope and remarkable functional group compatibility, this protocol offers access to various acyclic chiral organoboranes with structural diversity.
Fang et al. (Tue,) studied this question.