STEREOSELECTIVE TOTAL SYNTHESIS OF (+)-ARTEMISININ, THE ANTIMALARIAL CONSTITUENT OF ARTEMISIA-ANNUA L

A 10-step stereoselective total synthesis of the antimalarial cadinane sesquiterpene (+)-artemisinin (1) is described. Elaboration of (R)-(+)-pulegone to the known sulfoxide 11 was followed by dianion alkylation and desulfurization to provide the trans-2,3-substituted cyclohexanone 7. Homologation to the cyclohexenecarboxaldehyde 6 was followed by a diastereoselective silyl anion addition to afford the silyl acetate 15. Tandem Claisen ester-enolate rearrangement and dianion alkylation furnished the fully functionalized vinylsilane 18 that underwent abnormal ozonolysis and cyclization to provide the natural product 1.