ALPHA-HALOGENOKETONES .11. GENERALIZATION OF THE WHEELER AURONE SYNTHESIS

α-Bromo-β-methoxydihydrochalcones were generally available from the reaction of 2'-acetoxychalcones with N-bromosuccinimide in methanol and were cyclized by base to the corresponding aurones in excellent yield. An exception was the α-bromo-β-methoxydihydrochalcone derived from phloracetophenone which gave only a moderate yield of aurone. It formed, as the major product, a chromone epoxide, the rearrangement of which, in acidic conditions, constitutes a new chromonol synthesis. © 1979.