Treatment of 2-[l-(phenylthio) benzyl] cyclohexanol (2~) with N-chlorosuccinimide (NCS) and triethylamine gave various producta 3-6c depending on reaction conditions. Exclusive ring- opening reation of 2c was achieved by temperature control. Thus, five-, six-, and seven- membered cycloalkanols 2a-g were converted to W-OXO-a, p-unsaturated sulfides 6a-g in good yields. The stereochemistry of the reaction was determined by using four ...