Photochemical Hydrothiolation of Amorphadiene and Formal Synthesis of Artemisinin via a Pummerer Rearrangement

A new access to artemisinin is reported based on a selective photochemical hydrothiolation of amorphadiene, waste product the industrial semisynthetic route. This study highlights discovery two distinctive activation pathways under solvent-free conditions or using photocatalyst promoting H-abstraction. Subsequently, chemoselective oxidation resulting photochemically generated thioether, followed by Pummerer rearrangement, affords dihydroartemisinic aldehyde, key intermediate in synthesis artemisinin.