Nickel-Catalyzed [3+2+2] Cycloadditions between Alkynylidenecyclopropanes and Activated Alkenes

Now with nickel: [3C+2C+2C] cycloadditions involving non‐activated alkylidenecyclopropanes provide a practical entry to a variety of interesting 6,7‐fused bicyclic systems (see scheme; cod=1,5‐cyclooctadiene). DFT calculations, combined with experimental data, suggest that the catalytic cycle involves the initial formation of 1‐alkylidenenickelacyclobutane intermediates, such as 1.