Synthesis of Proline and 2-Piperidinecarboxylic Acid via Cobalt-Catalyzed Isomerization–Carbonylation of <i>N</i>-Acyl Unsaturated Cyclic Amines

Abstract

Abstract N-Acyl derivatives of proline and 2-piperidinecarboxylic acid (pipecolic acid) were synthesized in moderate yield from N-acyl unsaturated cyclic amines through cobalt-catalyzed isomerization–carboxylation under hydroformylation conditions in the presence of H2O. A possible mechanism for the process is discussed which is related to that of the amidocarbonylation (cobalt-catalyzed formation of N-acyl α-amino acid from aldehyde, amide and carbon monoxide).