Mild and efficient synthesis of trans-3-aryl-2-nitro-2,3-dihydrobenzofurans on water

An environmental-friendly and mild method has been successfully developed for the synthesis of 3-aryl-2-nitro-2,3-dihydrobenzofurans through domino Friedel–Crafts/substitution reaction of (Z)-bromonitrostyrenes with sesamol. A variety of substrates performed well in this reaction, and the corresponding 3-aryl-2-nitro-2,3-dihydrobenzofurans were obtained in excellent yields (up to 99%). Significantly, water served as the sole green solvent. Remarkably, the crude products were purified by simple filtration, washing with water and drying in oven without any organic solvents or silica gel.