Nickel‐Catalyzed Cascade Cyclization‐Negishi Coupling of Redox Active Esters for the Synthesis of Pyrrolidines

We have developed a Ni-catalyzed cascade cyclization/Negishi-coupling 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 proposed.