Treatment of 2-hydroxy-isoflav-3-ene with acid afforded 2-arylbenzofuran in goad yield and a mechanism for this chemical conversion involving loss of one carbon unit was described. This reaction scheme was suggested as a plausible chemical analogy for the corresponding biosynthetic process of 2-arylbenzofuran of isoflavonoid origin, and a new biosynthetic scheme depicting 2-hydroxy-isoflav-3-ene as the possible common intermediate for both 2-arylbenzofuran and 5-arylcoumarin was proposed. Synthesis of a potent antimicrobial 2-arylbenzofuran phytoalexin, vignafuran, was also achieved by use of this chemical scheme. Copyright (C) 1996 Published by Elsevier Science Ltd