Annulation of 4-Hydroxypyrones and α-Keto Vinyl Azides; A Regiospecific Approach towards the Synthesis of Furo[3, 2-c]Pyrone Scaffolds under Catalyst Free Condition

Abstract

A mild and efficient strategy for the construction of furo[3, 2-c]pyrones via an annulation of α-keto vinyl azides and 4-hydroxypyrones under catalyst free condition has been described. Several furo[3, 2-c]pyrone scaffolds were synthesized from readily available vinyl azides and 4-hydroxypyrones in a regiospecific manner. This protocol allows the formation of new C−O and C−C bonds in a single step to provide a wide variety of substituted furano heterocycles. It is worth noting that the present protocol has several advantages over the conventional methods such as catalyst free, short reaction duration and operational simplicity with good yields.