title: Formal total synthesis of (-)-taxol through Pd-catalyzed eight-membered carbocyclic ring formation.
abstract: A formal total synthesis of (-)-taxol by a convergent approach utilizing Pd-catalyzed intramolecular alkenylation is described. Formation of the eight-membered carbocyclic ring has been a problem in the convergent total synthesis of taxol but it was solved by the Pd-catalyzed intramolecular alkenylation of a methyl ketone affording the cyclized product in excellent yield (97 %), indicating the high efficiency of the Pd-catalyzed intramolecular alkenylation. Rearrangement of the epoxy benzyl ether through a 1,5-hydride shift, generating the C3 stereogenic center and subsequently forming the C1-C2 benzylidene, was discovered and utilized in the preparation of a substrate for the Pd-catalyzed reaction.
authors.affiliation: Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3240.
authors.forename: Sho
authors.initials: S
authors.lastname: Hirai
authors.forename: Masayuki
authors.initials: M
authors.lastname: Utsugi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Masahisa
authors.initials: M
authors.lastname: Nakada
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D008968:Molecular Conformation; D017239:Paclitaxel / Q000138:chemical synthesis* / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D010165:Palladium; D017239:Paclitaxel
keywords: cyclization; enantioselectivity; natural products; palladium; total synthesis