Catalytic Coupling of Ethylene and Internal Olefins by Dicationic Palladium(II) and Platinum(II) Complexes: Switching from Hydrovinylation to Cyclopropane Ring Formation

The dicationic palladium(II) and platinum(II) complexes [(PNP)M(C2H4)](BF4)2 (1a, M = Pt; 1b, M = Pd; PNP = 2,6-bis((diphenylphosphino)methyl)pyridine) and [(PPP)Pt(C2H4)](BF4)2 (7; PPP = triphos) catalyze a cross-coupling reaction of ethylene with tri- and tetrasubstituted olefins, which can lead to both hydrovinylation and cyclopropanation products. The product ratio is strongly affected by the choice of the ligand and of the metal, the two limiting cases being 1a and 7, which selectively give the hydrovinylation and the cyclopropanation products, respectively.