Abstract
The 1‐methoxy‐2‐(supermesitylphosphanylidenemethyl)‐benzene ligand (1) was prepared by reacting the phospha‐Wittig reagent [Mes*PPMe~3~] with o‐methoxybenzaldehyde. Reaction of 1 with one equivalent of the [Pd(allyl)Cl]~2~ dimer in the presence of Ag(OTf) affords a neutral complex (4) in which the triflate ligand is coordinated to the palladium atom. DFT calculations show that the formation of complex 4 is favored by 22.4 kcal/mol with respect to that of a chelate species involving coordination of the ligand through the phosphorus atom of one lone pair at the oxygen of the pendant methoxy group. Reaction of two equivalents of ligand 1 with the [Pd(allyl)Cl]~2~ dimer affords complex 5, in which the two ligands are coordinated through their phosphorus atom. The catalytic activity of complex 5 was compared to that of the 1,3‐bis[2‐(supermesityl)phosphanediylmethyl]benzene palladium chloride complex (6). Performances of the two catalysts were found to be similar in the Suzuki cross‐coupling reaction between phenylboronic acid and some arylbromides (TON between 55.10^5^ and 99.10^5^) as well as in the Sonogashira coupling between phenylacetylene and arylbromides (TON between 400 and 950). © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:363–371, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20307