DABCO-catalyzed multi-component domino reactions for the one-pot efficient synthesis of diverse and densely functionalized benzofurans in water

An efficient, three-component strategy for the improved synthesis of a pharmaceutically interesting diverse kind of multi-functionalized benzofurans via one-pot two-step domino protocol with high diastereoselectivity in excellent yields has been established. The synthesis was achieved by reacting phenacyl bromides, N-heterocycles, aromatic aldehydes, and cyclic 1,3-dicarbonyl compounds in the presence of a catalytic amount of DABCO (1,4-diazabicyclo[2.2.2]octane) as an inexpensive, impressive, and readily available catalyst in water under reflux. In this process in total three new bonds (two C–C and one C–O) form in one pot. Short reaction time, excellent yields, no chromatographic purification, and evasion of environmentally hazardous or toxic catalysts and organic solvents in the entire reaction process may make this protocol very useful for academia and industry.