A novel synthesis of 3-phenyl-4-hydroxycoumarins

Abstract

Several 2α-hydroxybenzyl-2,4,6-trimethoxycoumaran-3-ones which are substituted in the benzyl part have been found to undergo transformation in the presence of BF 3-etherate into the corresponding 3-phenyl-4-hydroxy-coumarins. Since these coumaranones are in turn readily obtainable from α-methoxychalkones, this constitutes a novel and useful synthesis of 3-phenyl-4-hydroxy-coumarins. It involves an acid catalysed rearrangement and suggests an alternative route of biogenesis of these natural products from the corresponding chalkones.