Long-lived polymer-supported dimeric Cinchona alkaloid organocatalyst in the asymmetric α-amination of 2-oxindoles

Abstract

Nearly quantitative yields and high enantiomeric purity (89–95% ee) were attained in the course of 100 reaction cycles of a polystyrene resin-supported Cinchona alkaloid organocatalyst in the enantioselective α-amination of 2-oxindoles with diethyl azodicarboxylate. The catalytic material proved stable for >5300 h operation time over 8 months