Reaction of ketenylidenetriphenylphosphorane, Ph3PC=C=O, with water: formation of methyltriphenylphosphonium hydrogencarbonate

The reaction of the oxocumulene ylide ketenylidenetriphenylphosphorane, Ph3PCCO (1), with an excess of water in THF yields a white microcrystalline solid, methyltriphenylphosphonium hydrogencarbonate, which contains one molecule of crystallization water, [Ph3MeP]CO3H·H2O (2). Compound 2 was characterized by IR, multinuclear NMR and ESI mass spectra. The chemical constitution was confirmed by X-ray crystal analysis. On heating, compound 2 decomposes giving CO2, H2O, C6H6 and Ph2MePO.