An efficient one-pot, regio- and stereoselective synthesis of novel pentacyclic-fused pyrano[3,2,c]chromenone or quinolinone benzosultone derivatives in water

A one-pot strategy has been developed for the synthesis of novel pentacyclic-fused pyranochromenone and pyranoquinolinone benzosultone derivatives. The in situ generated 2-formylphenyl-(E)-2-phenylethenesulfonates, from condensation of 2-hydroxybenzaldehydes with (E)-2-phenylethenesulfonyl chloride, underwent reaction with 4-hydroxycoumarins or 4-hydroxyquinolinone in water, affording the desired products in moderate to excellent yields. These reactions presumably proceed through O-sulfonylation/Knoevenagel condensation/hetero-Diels–Alder reaction cascade.