Abstract 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.
