A bimetallic aluminium(salen) complex for asymmetric cyanohydrin synthesis

In the presence of a phosphine oxide cocatalyst, a bimetallic aluminium(salen) complex was found to catalyse the asymmetric addition of trimethylsilyl cyanide to aldehydes. Under optimised conditions, enantioselectivities of 53–96% were obtained using 2 mol % of the catalyst. An analysis of the reaction kinetics showed that the reactions exhibited first-order kinetics, with the rate of reaction being independent of the aldehyde concentration.