Water-soluble ruthenium(II) catalysts [RuCl2(eta(6)-arene)-{P(CH2OH)(3)}] for isomerization of allylic alcohols and alkyne hydration

The novel water-soluble ruthenium(II) complexes [RuCl2(eta(6)-arene){P(CH2OH)(3)}] 2a-c and [RuCl(eta(6)-arene){P(CH2OH)(3)}(2)][Cl] 3a-c have been prepared in high yields by reaction of dimers [{Ru(eta(6)-arene)(mu-Cl)Cl}(2)] (arene = C6H6 1a, p-cymene 1b, C6Me6 1c) with two or four equivalents of P(CH2OH)(3), respectively. Complexes 2/3a-c are active catalysts in the redox isomerization of several allylic alcohols into the corresponding saturated carbonyl compounds under water/n-heptane biphasic conditions. Among them, the neutral derivatives [RuCl2(eta(6)-C6H6){P(CH2OH)(3)}] 2a and [RuCl2(eta(6)-p-cymene){P(CH2OH)(3)}] 2b show the highest activities (TOF values up to 600 h(-1); TON values up to 782). Complexes 2/3a-c also catalyze the hydration of terminal alkynes.