Abstract: Virtually complete asymmetric induction is achieved during methyl-, vinyl-, and naphthylmetallic conjugate addition to enantiomerically pure (S)-(+)-2-(p-tolylsulfinyl)-2- cyclopentenone ((S)-(+)-1).(R)-3-Methylcyclopentanone is obtained when the enone sulfoxide (S)-(+)-1 is first complexed with divalent zinc and then methylmagnesium iodide is added, whereas (S)-3-methylcyclopentanone is obtained when methylmagnesium iodide ...