Ion-pairing catalysis in the enantioselective addition of hydrazones to N-acyldihydropyrrole derivatives

Chem Commun (Camb). 2018 Aug 7;54(64):8905-8908. doi: 10.1039/c8cc05311a.

Abstract

We have demonstrated that dihydropyrrole-based enamide derivatives can act as efficient precursors of chiral quaternary N-acyliminium salts under Brønsted acid catalysis that undergo reactions with hydrazones, the latter participating as masked nucleophilic carbonyl group equivalents. The optimized methodology provides a variety of enantiopure α-substituted proline derivatives in excellent yields, being even compatible with disubstituted β-enamides that generate two contiguous stereocentres.