Facile synthesis of a monosulfonated triphenylphosphane (TPPMS) derived ligand having strong π-acceptor character

Two phenyl rings of triphenylphosphane have been modified by electron-withdrawing trifluoromethyl groups. A methoxy group has been introduced at the para-position of the third ring. Due to the activating effect of the methoxy group, the phosphane can be monosulfonated under mild conditions and with complete selectivity. The novel ligand, sodium 5-[bis-(4-trifluoromethylphenyl)phosphanyl]-2-methoxybenzenesulfonate, has been obtained in quantitative yield, and it has an outstanding pi-acceptor capacity among the known sulfonated triarylphosphanes. It is not soluble in water but soluble in light alcohols and ionic liquids. Its solubility properties allow facile catalyst separation without water.