Asymmetric metal free beta-boration of alpha,beta-unsaturated imines assisted by (S)-MeBoPhoz

The adduct [MeO -> Bpin-Bpin](-) efficiently mediates the beta-boration of alpha,beta-unsaturated imines formed in situ. The use of chiral phosphines as additives, and in particular the chiral phosphine (S)-MeBoPhoz, enables the catalytic asymmetric reaction to proceed with higher enantioselectivity than the analogue copper(I) mediated reaction.