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