Darstellung von (R)-2-(Sulfonyloxy)nitrilen und ihre Reaktionen mit Acetaten : Konfigurationsumkehr optisch aktiver Cyanhydrine (Enzym-katalysierte Reaktionen ; 15)

Abstract

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)-7,8í are unstable at higher temperature. The 2-(sulfonyloxy)nitriles (R)1- 6, 7, 8a - e react at room temperature with alkali acetates in a typical SN2 manner to give the cyanohydrin acetates (S)-9 in high optical purity. Under these reaction conditions, however, the mandelic-type compounds (R)-7, 8í partly racemize and decompose. By hydrolysis of the acetates (S)-9, (S)1-cyanohydrins (S)-2 of aliphatic aldehydes are easily available.