Ionic liquids as green solvents for the asymmetric synthesis of cyanohydrins catalysed by VO(salen) complexesDedicated to Prof. W. Adam on the occasion of his 65th Birthday.

It has been found that the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate is a good substitute solvent for CH2Cl2 to conduct the enantioselective cyanosilylation of aldehydes to their silylated cyanohydrins, using trimethylsilyl cyanide as reagent and a Schiff base vanadyl complex as catalyst. The mass balances (>90%), conversions (>80%) and enantiomeric excess (88% < ee < 90%) were high and comparable to those achieved in CH2Cl2. The ionic liquid containing the catalyst can be reused at least four times without loosing activity.