C3N4-Photocatalyzed aerobic oxidative cleavage of CC bonds in alkynes with diazonium salts leading to two different aldehydes or esters in one pot

摘要

A novel photocatalyzed radical addition/oxygen oxidation/cleavage of dioxetane/HAT domino process for cleavage of CC bonds has been described. This protocol used porous graphitic carbon nitrides (p-g-C3N4) as a metal-free recyclable photocatalyst for transformations of alkynes with diazonium salts to give two different aldehydes or esters, which enables the formation of multiple C-O bonds in a single reaction with operational simplicity. This reaction has an excellent substrate scope and gives the desired products in moderate to high yields. In addition, the heterogeneous semiconductor exhibits easy handling and excellent recyclability for at least 6 cycles without any apparent loss of activity. Furthermore, this reaction could be carried out under solar light irradiation and is applicable for the gram scale with satisfactory results.