A novel and stereospecific synthesis of aminocyclitol: N-tosyldihydroconduramine E2

A stereospecific synthesis of N-tosyldihydroconduramine E2, a new aminocyclitol, has been synthesised starting from cyclohexa-1,3-diene. The photooxygenation of cyclohexa-1,3-diene afforded the bicyclic endoperoxide. Reduction of the endoperoxide with thiourea and then reaction of the bis-carbamate with p-TsNCO followed by a palladium-catalysed ionisation/cyclisation reaction, gave a vinyl oxazolidin-2-one. Oxidation of the double bond in the oxazolidin-2-one with KMnO4 followed by acetylation, gave the oxazolidinone-diacetates. Hydrolysis of the oxazolidinone ring and removal of the acetate groups gave the desired aminocyclitol, N-tosyldihydroconduramine E2.