Method of producing (S)-cyanohydrins

A method of producing (S)-cyanohydrins of formula I ##STR13## wherein the groups R and R' signify, independently of one another:

• Hydrogen;
• A substituted or unsubstituted, linear or branched, saturated alkyl group with 1 to 18 C atoms wherein the substituents are one or several amino, imino, hydroxy, C.sub.1 -C.sub.8 -alkoxy, halogen, carboxyl, C.sub.3 -C.sub.20 -cycloalkyl groups and/or one optionally N,O,S-heteroatom-substituted aromatic ring with up to 22 C atoms as substituent, which cyclic substituents may be substituted themselves singly or multiply with halogen, hydroxy and/or linear or branched C.sub.1 -C.sub.8 -alkyl or C.sub.2 -C.sub.8 -alkenyl or C.sub.2 -C.sub.8 -alkinyl;
• A substituted or unsubstituted, linear or branched, singly or multiply unsaturated alkenyl- or alkinyl group with 2 to 18 C atoms wherein the substituents are one or several amino, imino, hydroxy, C.sub.1 -C.sub.8 -alkoxy, halogen, carboxyl, C.sub.3 -C.sub.20 -cycloalkyl groups and/or one optionally N,O,S-heteroatom-substituted aromatic ring with up to 22 C atoms as substituents, which cyclic substituents may be substituted themselves singly or multiply with halogen, hydroxy and/or linear or branched C.sub.1 -C.sub.8 -alkyl or C.sub.2 -C.sub.8 -alkenyl or C.sub.2 -C.sub.8 -alkinyl;
• A substituted or unsubstituted aromatic or heteroaromatic group with 5 to 22 ring atoms in which up to 4 of the ring carbon atoms may be replaced by N, O and/or S wherein the substituents are one or several amino, imino, hydroxy, C.sub.1 -C.sub.8 -alkoxy, aryloxy, halogen, carboxy and/or linear or branched, saturated or singly or multiply unsaturated alkyl groups with one to 22 C atoms
• as substituent and at least two of the substituents on the ring may be joined to a cycle,
• provided that R and R' are not both hydrogen,
• by enzyme-catalyzed conversion of carbonyl compounds of general formula II ##STR14## in which R and R' have the meaning indicated for formula I, with hydrogen cyanide or a substance supplying hydrogen cyanide or CN.sup.- for the reaction in the presence of an amount of an immobilized (S)-oxynitrilase which catalyses the reaction, wherein nitrocellulose is used as carrier for the immobilized (S)-oxynitrilase and the reaction is carried out in an organic solvent.