A CAN mediated oxidative coupling of 1,3-dicarbonyl compounds to 2-arylchromenes followed by cyclization affords tetrahydro-benzofuro[3,2-c]chromenones with regio- and diastereoselectivity in high yield.

Abstract

A promising and useful method has been accomplished for regio- and diastereoselective synthesis of tetrahydro-benzofuro[3,2-c]chromenones through ceric(IV) ammonium nitrate (CAN) mediated oxidative coupling of cyclic/acyclic 1,3-dicarbonyl compounds to 2-aryl/heteroarylchromenes followed by a base assisted cyclization. The significant features of the method encircle easy accessibility of the starting materials, high air stability and low toxicity of oxidant CAN, high product yield, operationally simple and eco-friendly reaction conditions. Trapping of a radical intermediate with radical scavenger TEMPO (detected by LC–MS) from the reaction mixture proved that the oxidative coupling is a radical mediated process.