Reactions of cyclopalladated compounds and alkynes: New pathways for organic synthesis?

Cyclometallated compounds, obtained by direct intramolecular C–H activation of a ligand by transition metals, are fairly reactive [especially those derived from palladium(II)] towards insertion of internal alkynes into their metal‐carbon bond. This reaction leads to either new organometallic compounds by inclusion of one to three alkynes into the M‐C bond, or organic compounds which are either carbocyclic or heterocyclic, their nature depending upon the alkyne substituents as well as upon the cyclometallated ligand.