NHC-catalyzed stereoselective synthesis of spirooxindole lactones from in situ generated oxindole-embedded o-quinone methides and aldehydes

Abstract

A novel N-heterocyclic carbene-catalyzed asymmetric [4 + 2] annulation of in situ generated oxindole-embedded o-quinone methides with aldehydes has been developed for synthesis of complicated spirooxindoles. The methodology provides facile, straightforward access to various enantioenriched spirooxindole lactones bearing a chiral quaternary carbon center in high yield (up to 98%) with diastereoselectivity (up to >20 : 1 dr) and excellent enantioselectivity (up to >99% ee).