Pd-Catalyzed Cross-Coupling of Terminal Alkynes with Chromium(0) Fischer Carbene Complexes.

Alkyl chromium(0) carbene complexes typically undergo cycloadditions with alkynes to afford carbo- or heterocyclic compounds. In the presence of Pd catalyst, it is demonstrated that a traditional cycloaddition pathway is completely altered: instead of cycloaddition, oxidative cross-coupling reaction of alkyl chromium(0) carbene complexes with terminal alkynes occurs. The coupling reaction exhibits excellent functional group tolerance and good efficiency.