Selective light supported oxidation of hexoses using air as oxidant - Synthesis of tetrahydroxyazepanes

Unprotected alkyl glycosides have been oxidized using air as oxidant and copper(I) chloride/TEMPO as the catalytic system. The primary hydroxy group in the 6 position is selectively transformed into an aldehyde equivalent. The process was optimized by irradiation with visible light. Without further purification and with high yields, the resulting lactols have been transformed into tetrahydroxyazepane.