Cinchona Alkaloid Squaramide Catalyzed Sulfa-Michael Addition

Significance An efficient cinchona alkaloid squaramide catalyzed asymmetric sulfa-Michael conjugate addition of thiols to trans -chalcones is described. Chen and co-workers applied the cinchona squaramide catalyst developed by Rawal’s group (J. P. Malerich, K. Hagihara, V. H. Rawal J. Am. Chem. Soc. 2008 , 130 , 14416) to sulfa-Michael reactions and the products were obtained in moderate to good yields as well as moderate to high enantioselectivities under mild reaction conditions.