BIOTRANSFORMATION OF ORGANIC SULFIDES .9. FORMATION OF (S)-PARASUBSTITUTED PHENYL METHYL SULFOXIDES BY BIOTRANSFORMATION USING HELMINTHOSPORIUM SPECIES NRRL-4671

Phenyl methyl sulfides substituted in the para position with methyl, f luoro, chloro, bromo, cyano, nitro, amino, acyl, methoxy, thiomethyl a nd methylsulfinyl groups have been converted to (S) sulfoxides by biot ransformation using Helminthosporium species NRRL 4671. The highest yi elds and enantiomeric excesses were obtained with bromo, cyano, methox y, thiomethyl and methylsulfinyl substituents and in two cases (para-B r and -CN) the products could be crystallized to give (S) sulfoxide of greater than or equal to 96% ee.