Stereoselective substitution of (R)-2-(sulfonyloxy)nitriles with sulfur nucleophiles

Optically active 2-(4-toluenesulfonyloxy)- and (4-nitrobenzenesulfonyloxy)nitriles (R)-3 and (R)-4, which were obtained from (R)-cyanohydrins (R)-2 by sulfonylation, react with sulfur nucleophiles such as potassium thioacetate, potassium ethylxanthogenate, potassium thiocyanate, as well as thioalcohols and thiophenol in a typical S(N)2 manner to give the (S)-2-sulfanyl nitriles (S)-7-9 and (S)-11-13 in good chemical yields and enantiomeric excesses. Even (R)-2-methyl-2-(methanesulfonyloxy)hexanenitrile (R)-6, derived from ketone cyanohydrin (R)-5, reacts with potassium thioacetate to yield (S)-2-acetylthio-2-methylhexanenitrile (S)-10 with 97% ee. (C) 1999 Elsevier Science Ltd. All rights reserved.