Beyond the Limits: Palladium‐N‐Heterocyclic Carbene‐Based Catalytic System Enables Highly Efficient [4+2] Benzannulation Reactions

A highly efficient catalytic system for the palladium‐catalyzed [4+2] benzannulation reaction of enynes and enynophiles has been developed. The use of an N‐heterocyclic carbene‐based palladium precursor allowed us to achieve turnover numbers up to 1800. The new catalytic system has enabled an expansion of the scope of the [4+2] homo‐benzannulation reaction.