Protonation and NMR studies on C-acetate enriched Ru(OAc)2(Binap). Acetate as a source of water in P---C bond splitting

The P---C bond splitting reaction of Ru(OAc)₂(Binap), containing ¹³C=O-enriched acetate, with 2 equiv. of triflic acid at 80 °C, has been studied. NMR spectroscopy (and specifically ¹³C NMR data) reveal that acetic anhydride and water are produced, thus explaining the end product, which may be thought of as developing due to water adding across the P---C bond. An intermediate 10 derived from attack of acetate on a P-atom is recognised. Complex 10 is shown to contain a cyclic five-membered ring, Ru---{(P---OC(Me)(=O)} fragment which develops via acetate attack on a P-atom. Crystal structures for two Ru(OAc)₂(MeO---Biphep) derivatives are reported.