Solvent-free synthesis of 4-aryl-3,4-dihydrobenzopyran-2-ones via [3+3] cyclocoupling of phenols with cinnamic acid catalyzed by molecular iodine

Molecular iodine was used as a catalyst in the [3+3] cyclocoupling of phenols and cinnamic acids which proceeds via a tandem esterification–hydroarylation process at 120–130 °C under solvent-free conditions. Substituted 4-aryl-3,4-dihydrobenzopyran-2-ones were obtained in good yields.