A practical high through-put continuous process for the synthesis of chiral cyanohydrins

A practical high through-put continuous process for the synthesis of chiral cyanohydrins is reported. Pretreated almond meal (or other solid raw enzyme sources) was loaded in a column to form a reactor, to which were attached a supplying system to deliver a solution of substrate and HCN in solvent on one end and a collecting-separating system on the other end. By controlling the flowing rate, optimal conditions were achieved for the hydrocyanation of various aromatic carboxaldehydes in a "micro-aqueous" medium to produce chiral cyanohydrins in high yields and high enantiomeric excess (ee) with high substrate/catalyst ratio.