ASYMMETRIC TOTAL SYNTHESIS OF TAXOL(R)

Asymmetric total syntheses of Taxol and of 8-demethyltaxoids 24-27 fro m the 8-membered ring compounds 29 and 12 respectively were completed via successive formation of the BC ring system by intramolecular aldol reaction, then the ABC ring system utilizing an intramolecular pinaco l cyclization. The conversion of the tricyclic compound 43 to 7-TES ba ccatin III (49) was carried out by way of a newly devised method of co nstructing the oxetane ring. The dehydration condensation between a de rivative of N-benzoylphenylisoserine and 49, followed by deprotection afforded the antitumor agent Taxol.