Transmetal-Catalyzed Enantioselective Cross-Coupling Reaction of Racemic Secondary Benzylic Bromides with Organoaluminum Reagents

The transmetal-catalyzed enantioselective cross-coupling reaction of secondary benzylic electrophiles with organoaluminum reagents has been developed. The reaction of secondary benzylic electrophiles with alkynylaluminum reagents provides a mild way for the chiral propargyl compounds bearing aromatic group in high yields with good enantioselectivities using NiBr₂·diglyme and (<i>R</i>)-<i>i</i>Pr-Pybox as the catalytic system. The reaction of secondary benzylic electrophiles with alkenylaluminum reagents affords the corresponding chiral aryl alkenes in moderate yields with excellent stereoselectivities using commercially available PdCl₂ and (<i>R</i>)-BINAP as the catalytic system