A base-catalyzed domino reaction between isoindigos and α-alkylidene succinimides-convenient preparation of highly steric bispirooxindoles.

A new base promoted Michael-Michael domino cycloaddition between isoindigos and α-alkylidene succinimides has been developed for highly efficient and one-step convenient preparation of highly steric bispiroxindoles with two adjacent quaternary carbon centers and four consecutive cycles in excellent yields (up to 96%) and diastereoselectivities (up to >20 : 1) under mild conditions within a few minutes. A series of bisprooxindoles were obtained and the synthetic potential of the protocol was evaluated in a scale-up preparation.