Total synthesis of tetracyclic sesquiterpenoids: (±)-ishwarone
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چکیده
منابع مشابه
Studies towards the total synthesis of lycoposerramine A. Synthesis of a model for the tetracyclic core.
Lycoposerramine A (1) is a pentacyclic alkaloid isolated in 2001 by Takayama and co-workers. A concise synthesis of a model compound 8 for the tetracyclic core of this natural product is described. Key steps include the desymmetrising free-radical cyclisation of compound 7 to give compound 18 and spirocyclisation of compound 26 to give compound 8. Earlier approaches using a novel high-yielding ...
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A catalytic enantioselective approach to the eudesmane sesquiterpenoids is reported. The strategic use of a palladium-catalyzed enantioselective alkylation of vinylogous ester substrates forged the C(10) all-carbon quaternary center. This key transformation enabled a diastereoselective olefin hydrogenation to create the syn stereochemistry at C(7). The devised synthetic strategy allowed for the...
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Plant extracts of the Celastraceae have been used for centuries throughout South America and China as insect repellents and insecticides in traditional agriculture, and also for the treatment of a plethora of medical ailments from stomach complaints and fever to rheumatoid arthritis and cancer. Many of the medicinally interesting properties associated with these crude preparations have now been...
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An efficient approach toward the synthesis of the 6,6,5,7-tetracyclic core of the daphnilongeranin B, a Daphniphyllum alkaloid, is reported. The bridged 6,6-bicyclic system was constructed using a gold(i) catalysed Conia-ene reaction, while the 5- and 7-membered rings were assembled by two diastereoselective Michael addition reactions, respectively.
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Synthesis Reaction of 1a,b with 2-aminothiophenol and sodium ethanolate in ethanol does not give the expected tetracyclic ring systems, but surprisingly the spirocompounds 2 are obtained. A [2+4] cycloaddition of the intermediately formed 1,2-benzoquinone-2-imine-1-thione with the aurone was postulated. Under these conditions the thioaurones 1c,d showed no reaction. After reaction of 1with 2-am...
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ژورنال
عنوان ژورنال: Canadian Journal of Chemistry
سال: 1980
ISSN: 0008-4042,1480-3291
DOI: 10.1139/v80-418