Synthesis of Adjacent Quaternary Stereocenters by Catalytic Asymmetric Allylboration

Allylboration of ketones with γ-disubstituted allyl­boronic acids is performed in the presence of chiral BINOL derivatives. The reaction is suitable for single-step creation of adjacent quaternary stereo­centers with high selectivity. We show that, with an appropriate choice of the chiral catalyst and the stereo­isomeric prenyl substrate, full control of the stereo- and enantio­selectivity is possible in the reaction.