Organocatalytic Enantioselective Vinylogous Aldol-Lactonization Cascade Reaction of 3-Alkylidene Oxindoles to Trifluoromethyl Ketones

In this work, an highly enantioselective vinylogous aldol-lactonization cascade reaction of 3-alkylidene oxindole to α,β-unsaturated trifluoromethyl ketone, promoted by bifunctional organocatalysts, is presented. The reaction proceed through 1,2-addition followed by cascade lactonization to afford an unsaturated lactone bearing a chiral trifluoromethylated tetrasubstituted carbon stereocenter with high enantioselectivity and moderate yield. Nevertheless, also the two E/Z isomers of the correspondent 1,2-addition product are obtained.