Asymmetric synthesis of cyanohydrins catalysed by a potassium Δ-bis[N-salicylidene-(R)-tryptophanato]cobaltate complex

A chiral cobalt(III) complex of a Schiff base derived from (R)-tryptophan and salicylaldehyde catalysed asymmetric trimethyl-silylcyanation of benzaldehyde at ambient temperature and a 20:1 substrate/catalyst ratio with the formation of enantiomerically enriched mandelonitrile (ee up to 77%).