From the structure of 3, 3-dimethyl-3H-benzofuro [3, 2-f][1]-benzopyran, a selective in vitro inhibitor of mycobacterial growth, we have undertaken a structure–activity relationship investigation. We wish to report here our results on the use of [2+ 3] cycloadditions between 2-formylbenzoquinone and various enol derivatives to give various 4-formyl-5-hydroxy benzofurans. In the next step, an ytterbium triflate-catalysed reaction with 2- ...
