Substituted (E)‐2‐Methylene‐3,4‐cyclohexenones through Direct and Convenient Synthesis from Cyclohexenone‐MBH Alcohol in the Presence of DMAP

An unexpected and effective DMAP catalyzed one‐step construction of 3,4‐cyclohexenone skeleton from simple and easily available cyclohexenone‐MBH alcohol has been disclosed. A series of substituted (E)‐2‐methylene‐3,4‐cyclohexenones have been effectively prepared in excellent yields (up to 93 %) under convenient reaction conditions. Succesful scale‐up preparation and synthetic transformations have demonstrated the potentials of this new protocol. An unexpected new reaction of cyclohexenone‐MBH alcohol catalyzed by DMAP has been successfully disclosed to prepare a series of substituted (E)‐2‐methylene‐3,4‐cyclohexenones in excellent yields (up to 93 %) under convenient reaction conditions. Scale‐up preparation and synthetic transformations have been conducted.