Regioselective Construction of Coumarin-1,2,4-triazines via a Cs2CO3-Catalyzed [3+3] Cycloaddition Reaction

Abstract

A cesium carbonate (Cs2CO3)-catalyzed [3 + 3] cycloaddition reaction of coumarin-diazo reagents with glycine imino esters is established to produce tetrahydro-1,2,4-triazines in good yields with excellent regioselectivity. One-pot cycloaddition/oxidation protocol could further provide practical access to a series of new coumarin-decorated 1,2,4-triazines.