Endo-Selective Construction of Spiro-[butyrolactone-pyrrolidine] via Ag(I)/CAAA-Amidphos-Catalyzed 1,3-Dipolar Cycloaddition between Azomethine Ylides and α-Methylene-γ-Butyrolactone

Abstract

Construction of spirocyclic pyrrolidines bearing a spiro quaternary stereocenter is an enormous challenge in synthetic organic chemistry. In this report, we introduce a Ag(I)/CAAA-amidphos-catalyzed enantioselective 1,3-dipolar cycloaddition between azomethine ylides and α-methylene-γ-butyrolactone as an effective strategy for the construction of excellent endo-selective spiro-[butyrolactone-pyrrolidine] derivatives. Meanwhile, the catalytic system was also successfully applied in the three-component one-pot reaction of azomethine ylides formed in situ under the action of N,N′-diisopropylcarbodiimide serving as a dehydrator. Under the optimal conditions, endo-pyrrolidine derivatives bearing a spiro quaternary stereocenter were obtained with high to excellent yields (up to 95% yield) and enantioselectivities (up to 93% ee).