- Synthesis of (+)-zerumin B using a regioselective singlet oxygen furan oxidation
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(Chemical Equation Presented) A short and efficient synthesis of the antitumor diterpenoid (+)-zerumin B has been accomplished starting from (+)-sclareolide. At the heart of the synthetic strategy lies the regioselective formation of the α-substituted γ-hydroxybutenolide moiety of zerumin B. This was achieved by means of a [1,4] O→C triisopropylsilyl migration followed by singlet oxygen (1O2) oxidation of the resulting 2-triisopropylsilyl-3-(α-hydroxy)alkylfuran.
- Margaros, Ioannis,Vassilikogiannakis, Georgios
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p. 2021 - 2023
(2008/09/21)
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- Synthesis of chinensines A-E
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(Chemical Equation Presented) Short and efficient syntheses of coronarin E (4) and chinensines A-E (5-9) have been accomplished. The use of two different types of reaction of singlet oxygen (1O2) lies at the heart of the synthetic st
- Margaros, Ioannis,Vassilikogiannakis, Georgios
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p. 4826 - 4831
(2008/02/05)
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- Trypanocidal labdane diterpenoids from the seeds of Aframomum aulacocarpos (Zingiberaceae)
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Two novel labdane type diterpenoids, 8β(17)-epoxy-14,15,16-trihydroxylabd-12(E)-ene (aulacocarpin C) and 15,16-epoxy-14ξ,16ξ-dimethoxylabda-8(17),12-(E)-diene (aulacocarpin D) together with the known aulacocarpin A and B; 14,15-epoxy-8(17),12(E)-labdadien-16-al, coronarin E, and 15,16-epoxy-12β-hydroxy-labda-8(17)-13(16),14-triene were isolated from the seeds of Aframomum aulacocarpos. To the best of our knowledge, the last compound was isolated from a natural source for the first time. Acid hydrolysis of aulacocarpin D led to another new labdane type diterpenoid, 15,16-epoxy-12β-methoxylabda-8(17)-13(16),14-triene. The structures of all compounds were established on the basis of their spectroscopic data. These new compounds exhibit moderate trypanocidal activity.
- Sob, Sylvain Valère T.,Tane, Pierre,Ngadjui, Bonaventure T.,Connolly, Joseph D.,Ma, Dawei
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p. 8993 - 8998
(2008/02/10)
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- Facile access to labdane-type diterpenes: Synthesis of coronarin C, zerumin B, labda-8(17), 13(14)-dien-15,16-olide and derivatives from (+)-manool
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A practical method for the synthesis of optically active labdane-type diterpenes from (+)-manool 8, is described. We prepared the natural labdane-type diterpene 5 via key intermediate peroxide 9 and coronarin C 1, compound 8 and zerumin B 6 via a furan photosensitised oxygenation reactions.
- Villamizar, Jose E.,Juncosa, Jose,Pittelaud, Jean,Hernandez, Madeleyn,Canudas, Nieves,Tropper, Eleonora,Salazar, Franklin,Fuentes, Juan
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p. 342 - 346
(2008/02/12)
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- Synthesis and stereochemistry of the antitumor diterpenoid (+)-zerumin B
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Starting from commercially available (+)-sclareolide, the first synthesis of zerumin B was achieved by a concise, highly efficient pathway featuring stereoselective addition of a new silyloxyfuryltitanium reagent to an aldehyde intermediate and silyloxyfuran oxyfunctionalization as key steps. The synthesis established the relative and absolute configuration of zerumin B along with its identity with a purportedly new diterpenoid isolated from the plant Renealmia alpinia.
- Boukouvalas, John,Wang, Jian-Xin,Marion, Olivier,Ndzi, Bruno
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p. 6670 - 6673
(2007/10/03)
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- Synthesis of the marine furanoditerpene (-)-marginatone
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A synthesis of the marine labdane furanoditerpene (-)-marginatone 1 has been accomplished by a short sequence of reactions starting from (+)-coronarin E 5. The key step is the stereocontrolled-intramolecular electrophilic cyclisation of the (+)-dihydrocoronarin E 6, to the tetracyclic marginatane skeleton 7, which is subsequently functionalized by allylic oxidation to give 1. As (+)-coronarin E 5 was previously synthesized from (-)-sclareol 10, the herein reported preparation constitutes the first formal total synthesis of (-)-marginatone 1, by which its absolute configuration has been confirmed.
- Kolympadi, Maria,Liapis, Maria,Ragoussis, Valentine
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p. 2003 - 2010
(2007/10/03)
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