Nickel-Catalyzed cascade Cyclization-Negishi coupling of redox active esters for the synthesis of pyrrolidines

Abstract

We have developed a Ni-catalyzed cascade cyclization/Negishicoupling reaction for the formation of pyrrolidines and pyrrolidinones starting from N-protected allylamines and acrylamides which contain a redox active ester group. The reaction provides two C C bonds in a single operation and takes place with both alkylzinc and arylzinc bromides as nucleophiles. Activation of RAE by low valent Ni complexes involving a radical pathway followed by a fast cyclization of intermediate carbon radicals is propose