ENZYME-CATALYZED REACTIONS .15. PREPARATION OF (R)-2-(SULFONYLOXY)NITRILES AND THEIR REACTIONS WITH ACETATES - INVERSION OF THE CONFIGURATION OF OPTICALLY-ACTIVE CYANOHYDRINS

2-(Sulfonyloxy)nitriles (R)-6,7,8 are obtained in high optical purity from the respective cyanohydrins (R)-2 by sulfonylation with methanesulfonyl chloride (3), toluenesulfonyl chloride (4), and trifluoromethanesulfonic anhydride (5), respectively. In contrast to the aliphatic (sulfonyloxy)nitriles (R)-6,7,8a-e, the benzylic-type mandelic acid derivatives (R)-7,8f are unstable at higher temperature, The 2-(sulfonyloxy)nitriles (R)-6,7,8a-e react at room temperature with alkali acetates in a typical S(N)2 manner to give the-cyanohydrin acetates (S)-9 in high optical purity. Under these reaction conditions, however, the mandelic-type compounds (R)-7,8f partly racemize and decompose. By hydrolysis of the acetates (S)-9, (S)-cyanohydrins (S)-2 of aliphatic aldehydes are easily available.