N-Arylprolinamide as an organocatalyst for the direct asymmetric aldol reaction of acetone with isatin

Abstract N -Aryl-( S )-prolinamides act as organocatalysts for the direct asymmetric aldol reaction between isatin and acetone. N -(4-Bromophenyl)-( S )-prolinamide (20 mol %) efficiently catalysed the direct aldol reaction between isatin and acetone at −35 °C, and afforded 3-alkyl-3-hydroxyindolin-2-one in 99% yield and with 71% ee. We have generalised the methodology for the direct asymmetric aldol reaction between isatin derivatives and acetone, and the corresponding aldol products were obtained in 76–99% yields and with 42–87% ee.