Catalytic Enantioselective Conjugate Addition of Cyanide to α,β-Unsaturated N-Acylpyrroles

Abstract
A catalytic enantioselective conjugate addition of cyanide to α,β-unsaturated N-acylpyrroles was developed using the chiral gadolinium catalyst generated from Gd(OiPr)3 and d-glucose-derived ligand 2. Generally high enantioselectivity was obtained from a wide range of substrates; substrates with β-aryl and β-vinyl substituents and α,β-disubstituted substrates can now be used. Using this reaction as a key step, short-step syntheses of several pharmaceuticals and their lead compounds were achieved, including the β-phenyl-substituted GABA analogue and pregabalin.