Unprecedented rhodium-mediated catalytic transfer hydrogenation of a phosphonate functionalized olefin in ecofriendly media

RhCl3 · xH2O catalyst-mediated hydrogenation reactions of vinyl phosphonic diethyl ester H2CCH–P(O)(OEt)2 (1) have been investigated. Results demonstrate that the hydrogenation of H2CCH–P(O)(OEt)2 (1) to CH3CH2–P(O)(OEt)(OH) (2) proceeds in the presence of RhCl3 · xH2O catalyst, without any external hydrogen source and ancillary ligands, to near qualitative yields in ethanol and water media. 31P, 13C and 1H NMR and deuterium-labeling experiments provide evidence for the non-concerted mechanistic pathway associated with the hydrogenation of 1 to 2.