Preparation of Chiral 1-Deuteriobenzenemethanethiols by Using α',β Elimination of Carbanions Derived from Benzylic Thioethers

Article abstract of DOI:10.1021/jo00136a014

The α',β elimination of the carbanion derived from <α-2H2>benzyl isolongifolyl thioether and <α-2H2>benzyl camphyl thioether gives the chiral <α-2H>benzyl mercaptan, the S isomer with 38 +/- 6percent ee and the R isomer with 49 +/- 7percent ee.The chirality of the <α-2H>benzyl mercaptan was determined by optical rotation of <α-2H>benzyl methyl thioether and thiosulfone.The enantiomeric excess was evaluated from 1H NMR measurement of ethyl (benzylthio)phenylacetate prepared from (-)-mandelic acid.The enantiomeric excess at carbon C-2 of ethyl (benzylthio)phenylacetate wasdetermined with the chiral europium chelate and was about 60percent.These results are discussed with reference to the transition state of the α,β elimination and to related processes.