A Catalyst-Free One-Pot Construction of Skeletons of 5-Methoxyseselin and Alloxanthoxyletin in Water

In refluxing water and without an additional catalyst, electron-rich phenols could react with alkynoic acids or alkynoates to provide coumarin structures. The skeletons of two natural pyranocoumarins, 5-methoxyseselin and alloxanthoxyletin, could be constructed (total yield up to 76%) in an aqueous multicomponent reaction in which isoprenyl acetate, propiolic acid, and phloroglucinol were simply mixed and refluxed in water.