A coordination controlled aryl-halide oxidative addition to platinum

Aryl-halide bond activation and coordination of unsaturated substrates are key steps in many metal-mediated carbon-carbon bond-forming reactions. A series of reactions with stillbenes 1-7 and Pt(PEt₃)₄ were used to explore the role of substrate coordination on aryl-halide activation. The complexes 8-14 were characterized by NMR spectroscopy, and complexes 9-12 and 14 were isolated and characterized by elemental analysis. Nearly identical spectroscopic properties were reported for structurally related stillbazole complexes. Prolonged reaction times and elevated temperatures resulted in the quantitative formation of complexes 15-21. The X-ray structure of complex 12, confirms the n²-coordination of the central carbon-carbon double bond of the stillbene to the metal center. A good linear correlation was observed between the rates of these transformations and the electronic properties of the substituent of the stillbenes.