Enantioselective Conjugate Hydrocyanation of α,β-Unsaturated N-Acylpyrroles Catalyzed by Chiral Lithium(I) Phosphoryl Phenoxide

Enantioselective conjugate hydrocyanation of α,β-unsaturated N-acylpyrroles with the combined use of Me3SiCN, LiCN, and HCN has been developed in the presence of a chiral lithium(I) phosphoryl phenoxide catalyst. This reaction is useful for a variety of N-acylpyrroles, including previously unreported substrates, such as heteroaryl and halogen-substituted N-cinnamoylpyrroles. A gram-scale reaction and subsequent transformations to a (R)-succinate, (S)-paraconic acid, and (R)-baclofen demonstrate an entry for the practical synthesis of optically active β-substituted γ-aminobutyric acids (GABA).