Chiral synthetic unprecedented spiro[indoline-2,3'-thiophen]-3-ones via organocatalytic asymmetric sulfa-Michael/aldol cascade reaction

An asymmetric sulfa-Michael/aldol cascade reaction of 2-ylideneoxindoles with 1,4-dithiane-2,5-diol catalyzed by squaramide derived from cinchona was first developed to realize the chiral synthesis of unprecedented C2-spirooxindoles with a 3-amine-tetrahydrothiophene moiety...