Solvent-Free Synthesis of Chiral Schiff-Base Ligands Based on Ferrocene under Microwave Irradiation and Application to Enantioselective Nitroaldol (Henry) Reaction

Abstract

Chiral Schiff-bases 3a-f based on ferrocene were designed and synthesized using solvent-free methods by mixing ferrocene carbaldehyde 1 with amino alcohols and amines 2a-f under microwave irradiation and classical method for the enantioselective nitroaldol (Henry) reaction. The Schiff-bases were obtained in shorter reaction times and improved yield under microwave irradiation method over classical method. The highest enantioselectivity was observed in ligand 3e (95% ee) when CH(2)Cl(2) was used as solvent. Chirality 23: 374-378, 2011. (c) 2011 Wiley-Liss, Inc.