REPLACEMENT OF THE NONPEROXIDIC TRIOXANE OXYGEN-ATOM OF ARTEMISININ BY CARBON - TOTAL SYNTHESIS OF (-13-CARBAARTEMISININ AND RELATED STRUCTURES())

Provided by total synthesis, endoperoxides 17, 19 and 21 underwent int ramolecular oxymercuration-demercuration leading respectively to forma tion of an isomeric tetracycle, 3S,5aS,6R,8aS,9R,12S)-10-deoxo-13-carb aartemisinin 18, (+)-10-deoxo-13-carbaartemisinin 20, and (+)-13-carba artemisinin 4. Neither target 4 nor 20 displayed substantial antimalar ial potency in vitro against Plasmodium falciparum, but the isomeric p eroxide 18 possessed reasonable antimalarial potency in vitro.