- Stereoselective synthesis of the ABC ring system of norzoanthamine
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(Equation presented) An efficient synthesis of enone 4, representing the ABC ring motif of norzoanthamine, is presented. The crucial C22 quaternary center was introduced via a stereoselective methylation of enone 8. The trans-anti-trans relative configura
- Ghosh, Subhash,Rivas, Fatima,Fischer, Derek,Gonzalez, Miguel A.,Theodorakis, Emmanuel A.
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- Ethyl 5-[(4-methylphenyl)sulfonyl]-3-oxopentanoate: A bench-stable synthon for ethyl 3-oxopent-4-enoate (Nazarov's Reagent)
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The easily available adducts of sodium p-toluenesulfinate to both acrylonitrile or acrylic acid were efficiently transformed through a two-step, high-yielding sequence into ethyl 5-[(4-methylphenyl)sulfonyl]-3-oxopentanoate, a convenient source for the popular Nazarov's reagent, ethyl 3-oxopent-4-enoate, which could be generated in situ by base-induced β-elimination and used for annulation reactions.
- Benetti, Simonetta,Carli, Stefano,De Risi, Carmela,Pollini, Gian P.,Veronese, Augusto C.,Zanirato, Vinicio
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scheme or table
p. 2609 - 2612
(2009/04/17)
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- Enantioselective synthesis of the antiinflammatory agent (-)-acanthoic acid
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An enantioselective synthesis of the potent antiinflammatory agent (-)-acanthoic acid (1) is described. The successful strategy departs from (-)-Wieland-Miescher ketone (10), which is readily available in both enantiomeric forms and constitutes the starting point toward a fully functionalized AB ring system of 1. Conditions were developed for a regioselective double alkylation at the C4 center of the A ring, which produced compound 32 as a single stereoisomer. Construction of the C ring of 1 was accomplished via a Diels-Alder reaction between sulfur-containing diene 43 and methacrolein (36), which after desulfurization and further functionalization yielded synthetic acanthoic acid. The described synthesis confirms the proposed stereochemistry of the natural product and represents a fully stereocontrolled entry into an underexplored class of biologically active diterpenes.
- Ling,Chowdhury,Kramer,Vong,Palladino,Theodorakis
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p. 8843 - 8853
(2007/10/03)
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- Application of the Nickel-Mediated Neopentyl Coupling in the Total Synthesis of the Marine Natural Product Arenarol
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Racemic arenarol (1) has been synthesized from the known decalin 5β-carbethoxy-1,1-(1,2-ethylenedioxy)-5α,8aβ-dimethyl-1,2,3,5,6,7,8,8a-octahydro-6-oxonaphthalene (9) via a short, efficient, and highly stereocontrolled sequence.Key steps in this synthesis are the directed hydrogenation of an unsaturated neopentyl alcohol to provide stereocontrolled formation of the two adjacent tetriary centers and subsequent elaboration of the arenarol skeleton via a nickel-mediated coupling of the corresponding neopentyl iodide.This sequence demonstrates the value of nickel-mediated crosscoupling reactions for carbon-carbon bond formation at neopentyl centers.
- Watson, Anthony T.,Park, Kwangyong,Wiemer, David F.,Scott, William J.
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p. 5102 - 5106
(2007/10/02)
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- FACILE SYNTHESIS OF ALKYL 5-ALKOXY-3-OXOPENTANOATES
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A facile synthesis of several alkyl 5-alkoxy-3-oxopentanoates, based on the reductive elimination of triphenylphosphine from the readily available alkyl 5-alkoxy-3-oxo-2-(triphenylphosphoranylidene) pentanoates, is described.
- Sanchez, Ignacio H.,Larraza, Maria Isabel,Brena, Francisco Kuri,Cruz, Adrian,Sotelo, Octavio,Flores, Humberto J.
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p. 299 - 308
(2007/10/02)
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