Cooperative Catalysis for the First Asymmetric Formal [3+2] Cycloaddition Reaction of Isocyanoacetates to α,β-Unsaturated Ketones

A cooperative multicatalytic cascade sequence involving isocyanoacetates and alpha,beta-unsaturated ketones is described for the enantioselective synthesis of 2,3-dihydropyrroles. The key to promoting the multistep asymmetric reaction is the combination of cinchona alkaloid derived organocatalysts with silver nitrate. Merging both organic and metal catalytic cycles enables the formation of two C-C bonds and the generation of a stereogenic center in a single process. The study has also shown that the bifunctional role of the organocatalyst is crucial for the asymmetric version of the cycloaddition reaction.