Asymmetric formal [3+2] cycloaddition reaction of α-aryl isocyanoesters with N-aryl maleimides by bifunctional cinchona alkaloids-based squaramide/AgSbF6 cooperative catalysis.

It is better to be cooperative: A highly diastereo- and enantioselective asymmetric [3+2] cycloaddition reaction of α-aryl isocyanoacetates with N-aryl maleimides through cooperative catalysis of cinchona alkaloid-derived squaramide/AgSbF(6) was developed. A wide range of optically active, substituted 1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c] pyrrole derivatives was obtained in high yields (up to 98%), high diastereoselectivities (>20:1 d.r.), and good to excellent enantioselectivities (up to 92% ee) under mild reaction conditions.