title: Enantioselective total syntheses of cyathane diterpenoids.
abstract: A Personal Account describing the enantioselective total syntheses of cyathane diterpenoids achieved in the Nakada group. A convergent approach to the cyathane scaffold, the [5-6-7] tricyclic carbon skeleton commonly found in cyathane diterpenoids, has been developed using the catalytic asymmetric intramolecular cyclopropanation (CAIMCP) and baker's yeast reduction. This approach has been successfully applied for the enantioselective total syntheses of (+)-allocyathin B2 , (-)-erinacine B, and (-)-erinacine E. The total synthesis of (-)-erinacine E has been achieved via the acyl group migratory intramolecular aldol reaction, which prevents the retro-aldol reaction and allows the construction of the strained structure. The highly efficient and stereoselective total syntheses of (-)-scabronines G, A, D, and (-)-episcabronine A have been achieved via the oxidative dearomatization/inverse electron demand Diels-Alder reaction cascade. Cascade reactions comprising three and five consecutive reactions were employed for the highly efficient total syntheses of (-)-scabronine A and (-)-episcabronine A, respectively.
authors: Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan. mnakada@waseda.jp.
authors: Masahisa
authors: M
authors: Nakada
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis / Q000737:chemistry; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D004224:Diterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis / Q000737:chemistry; D013141:Spiro Compounds / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D001572:Benzofurans; D001688:Biological Products; D004224:Diterpenes; D006576:Heterocyclic Compounds, 4 or More Rings; D013141:Spiro Compounds; C430643:allocyathin B2; C497675:cyathane; C518057:erinacine B; C116931:erinacine E; C119786:scabronine A; C119787:scabronine G
keywords: asymmetric synthesis; cascade reactions; cyathanes; natural products; total synthesis