Sequential Pd-Catalyzed Asymmetric Allene Diboration/α-Aminoallylation

Abstract

Pd-catalyzed enantioselective diboration of prochiral allenes provides adducts which participate in highly selective allylation reactions with primary imines. The allylation product is a vinyl boronate which may be oxidized to give nonracemic Mannich products (87-97% ee). Alternatively, enantiomerically enriched homoallylic amine derivatives may be obtained by protonation and Suzuki cross-coupling of the vinyl boronate.