Efficient Synthesis of Polycyclic γ‐Lactams by Catalytic Carbonylation of Ene‐Imines via Nickelacycle Intermediates

The nickel(0)‐catalyzed carbonylative cycloaddition of 1,5‐ and 1,6‐ene‐imines with carbon monoxide (CO) is reported. Key to this reaction is the efficient regeneration of the catalytically active nickel(0) species from nickel carbonyl complexes such as [Ni(CO)3L]. A variety of tri‐ and tetracyclic γ‐lactams were thus prepared in excellent yields with 100 % atom efficiency. Preliminary results on asymmetric derivatives promise potential in the synthesis of enantioenriched polycyclic γ‐lactams. CO‐Gas wurde in einer Nickel(0)‐katalysierten carbonylierenden [2+2+1]‐Cycloaddition mit 1,5‐ und 1,6‐Eniminen eingesetzt. Die Methode liefert eine Vielzahl von tri‐ und tetracyclischen γ‐Lactamen in exzellenten Ausbeuten mit 100 % Atomeffizienz.