A Metal‐Free Synthesis of 2‐Alkyl(or Aryl) Thiomethyl‐2‐cyclohexenones from Cyclic Morita–Baylis–Hillman Bromides

Under mild conditions, an efficient and rapid S‐allylation of thiols with cyclic Morita–Baylis–Hillman (MBH) bromides without the need of a transition‐metal catalyst or an expensive additive is described herein. Treatment of the MBH bromides with various thiols or ethane‐1,2‐dithiol in the presence of Et₃N regioselectively affords the corresponding 2‐alkyl(or aryl) thiomethyl‐2‐cyclohexenones or the perhydro benzo1,4]dithiepinone, respectively, in moderate to good yields (40 – 73%). The reaction is rapid and carried out in THF at room temperature.