Chiral amide from (1S, 2R)-(+)-norephedrine and furoic acid: An efficient catalyst for asymmetric Reformatsky reaction

Abstract

Chiral amide derived from (1S, 2R)-(+)-norephedrine and 2-furoic acid was found to catalyse the asymmetric Reformatsky reaction between prochiral aldehydes and α-bromo ethylacetate with diethylzinc as zinc source. The corresponding chiral β-hydroxy esters were formed in 99% yield with over 80% enantiomeric excess. The presence of air was found to be essential for the effective C-C bond formation. The mechanism for the catalytic reaction was proposed. Chiral Ligand (CL) synthesized from (1S, 2R)-(+)-norephedrine and 2-furoic acid was found to catalyse asymmetric Reformatsky reaction. The chiral products were formed in 95% yield with over 90% ee in some of the cases. It was found that the presence of air is essential for effective C-C bond formation.