Chiral 1,2,5-triphenylphospholanium tetrafluoroborate as ligand precursor in Rh-catalyzed asymmetric hydrogenation of methyl (Z)-2-acetamidocinnamate

(S,S)-1,2,5-Triphenylphospholanium tetrafluoroborate salt 2 was conveniently used as chiral ligand precursor in rhodium-catalyzed asymmetric hydrogenation of methyl (Z)-2-acetamidocinnamate. 31P NMR showed the existence of a solvent-dependent equilibrium between the salt and the free phosphine.