Coupling of Internal Alkynes in Tp Me2 Ir Derivatives: Selective Oxidation of a Noncoordinated Double Bond of the Resulting Iridacycloheptatrienes

The reaction of different Tp(Me2)Ir derivatives and dimethylacetylene dicarboxylate (DMAD) allows the preparation of three different metallacycloheptatriene complexes and an unusual allyl-terminated metallacycle. The C atoms of distant C=C bonds in the metallacycles, including aromatic ones, can be converted selectively to the corresponding keto functionality under mild conditions.