An Unusual Migratory Insertion of CO into a Pentamethylcyclopentadienyl−Platinum Bond

Instead of undergoing the expected ligand substitution reaction when treated with PMe3, the pentamethylcyclopentadienyl−platinum complex Cp*Pt(CO)I (1c) adds 2 equiv of phosphine to give the first example of a CO insertion reaction into a transition-metal−Cp* bond. The acyl product, trans-Pt(COC5Me5)(I)(PMe3)2 (5), has been characterized by single-crystal X-ray diffraction study and appears to be the first reported example of this (cyclopentadienyl)acyl structural motif.