Cyanide ion cocatalysis in Ti(salen) catalysed asymmetric cyanohydrin carbonate synthesis.

In the presence of potassium cyanide or the potassium cyanide/18-crown-6 complex as a cocatalyst, 1-2 mol% of titanium(salen) complex catalyses the asymmetric addition of achiral cyanoformates to aldehydes, giving cyanohydrin carbonates with high enantiomeric excesses; and catalyses the diastereoselective addition of chiral cyanoformates derived from alpha-methylbenzyl alcohol to aldehydes, a reaction which exhibits double asymmetric induction.