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.