Copper-Catalyzed Asymmetric Hydroboration of 1,1-Disubstituted Alkenes.

A mild and efficient approach for highly regio- and enantioselective copper-catalyzed hydroboration of 1,1-diaryl substituted alkenes with bis(pinacolato)diboron (B2Pin2) was developed for the first time, providing facile access to a series of valuable β,β-diaryl substituted boronic esters with high enantiomeric purity. Moreover, this approach could also be suitable for hydroboration of α-alkyl styrenes for the synthesis of enantioenriched β,β-arylalkyl substituted boronic esters. Gram-scale reaction, stereospecific derivatizations, and the application of important antimuscarinic drug (R)-tolterodine for concise enantioselective synthesis further highlighted the attractiveness of this new approach.