Chiral borophosphate catalyzed asymmetric hydroamination of alkenes

Abstract

Chiral pyrrolidines are key motifs in natural products and pharmaceutically active intermediates. Herein, we report a metal-free enantioselective intramolecular hydroamination of alkenes catalyzed by a chiral borophosphate. This chiral frustrated Lewis pair (FLP)-type catalyst outperforms chiral phosphoric acid alone, furnishing chiral pyrrolidines in up to 96% yield and 95% ee. This work extends the utility of chiral FLP catalysis to non-reductive asymmetric cyclization reactions.