Vanadium-catalyzed asymmetric cyanohydrin synthesis

[GRAPHICS] Based on a mechanistic understanding of asymmetric cyanohydrin synthesis catalyzed by chiral titanium-salen complexes, a new catalyst based on vanadlum(IV) has been developed. The chiral (salen)VO catalyst is more enantioselective than the titanium based systems, 0.1 mol % of the catalyst being sufficient to convert aromatic and aliphatic aldehydes into the corresponding trimethylsilyl ethers of cyanohydrins with 68-95% enantiomeric excess at room temperature.