Enantioconvergent Hydroboration of /-Mixed Trisubstituted Alkenes.

The lack of mode for chirality recognition makes it particularly challenging to carry out asymmetric transformations on /-mixed minimally functionalized trisubstituted alkenes. Here, we report a catalytic enantioconvergent hydroboration of minimally functionalized trisubstituted /-mixed alkenes to construct chiral organoboronic esters with excellent enantioselectivity using chiral radical cobalt catalyst. This C(sp)-H borylation protocol showed good functional group tolerance and products could be converted to valuable compounds via C-B derivatizations. The mechanistic studies, which included control experiments, nonlinear effect experiments, deuterated labeling experiments, and X-ray diffraction, demonstrated that the favorable compatibility between the thermodynamically unfavorable isomerization and hydroboration was the key factor in achieving convergent transformation.