Curcumin as a Cinnamoyl Transfer Reagent via C–C(CO) Bond Scissoring in the Microwave-Assisted Reaction with Hydroxy-p-QMs

Abstract

A microwave-assisted cascade conjugate addition–intramolecular cinnamoyl transfer (“cut and sew”) strategy involving 2-hydroxyphenyl-para-quinone methides (HPQMs) and curcumins, yielding cinnamoyl cinnamates bearing a diarylalkyl moiety in excellent yields and with broad substrate versatility, is reported. Mechanistic studies revealed a cascade Michael–hemiketalization–retro-Claisen reaction resulting in the C–C(CO) bond cleavage of curcumin. Furthermore, the cinnamoyl transfer products are amenable for a variety of synthetic transformations, highlighting their significance and synthetic utility.