Three-component reactions based on trapping ammonium ylides with N-sulfonyl aldimines via cooperative catalysis of squaramides and Rh2(OAc)4

Three-component reactions of aryl diazoacetates, arylamines and N-sulfonyl aldimines cooperatively catalyzed by squaramides and dirhodium acetate are reported to afford N-sulfonyl α,β-diamino acid derivatives in moderate to good yields and diastereoselectivity.