Catalysed oxygenation of allylic hydroperoxides derived from qinghao (artemisinic) acid. Conversion of qinghao acid into dehydroginghaosu (artemisitene) and qinghaosu (artemisinin)

Abstract

Photo-oxygenation of ginghao acid and its dihydro analogue provides allylic hydroperoxides which are converted either indirectly via the corresponding esters, or directly into dehydroginghaosu (artemisitene) and the antimalarial ginghaosu (artemisinin), by treatment with a catalytic amount of copper(II) trifluoromethanesulphonate with or without an iron(III) co-catalyst in dichloromethane-acetonitrile under oxygen.