- Diastereoselective Synthesis of (±)-Epianastrephin, (±)-Anastrephin and Analogs Thereof
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A process for the synthesis of trans-fused γ-lactones having Formula (IV) from substituted cyclic ketones having Formula (I). A diastereoselective synthesis of (±)-epianastrephin (1) (wherein: R1 is ethenyl, R2 and R3 is methyl, and n is 1), (±)-anastrephin (2) (wherein: R2 is ethenyl, R1 and R3 is methyl and n is 1), and analogs thereof (wherein: R1 is H, C1-5 alkyl, C2-6 alkenyl or C2-6 alkynyl, R2 is H, C1-5 alkyl, C2-6 alkenyl or C2-6 alkynyl, R1 and R2 together with the carbon atom they are attached form a C3-6 cycloalkyl ring, R3 is C1-5 alkyl and n is 0-2):
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Paragraph 0080; 0081
(2017/11/14)
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- Bismesitylmagnesium: A thermally stable and non-nucleophilic carbon-centred base reagent for the efficient preparation of silyl enol ethers
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Bismesitylmagnesium has been established as an accessible, practical, convenient, and non-nucleophilic carbon-centred base reagent for efficient access to silyl enol ethers from a series of ketone substrates at readily utilisable temperatures. The Royal Society of Chemistry.
- Kerr, William J.,Watson, Allan J. B.,Hayes, Douglas
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p. 5049 - 5051
(2008/09/17)
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- Silazanes/catalytic bases: Mild, powerful and chemoselective agents for the preparation of enol silyl ethers from ketones and aldehydes
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We have developed an efficient method for the preparation of enol silyl ethers using novel agents, silazanes together with NaH or DBU catalyst, wherein TMS and TBDMS groups were smoothly and chemoselectively introduced into ketones and aldehydes under mil
- Tanabe, Yoo,Misaki, Tomonori,Kurihara, Minoru,Iida, Akira,Nishii, Yoshinori
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p. 1628 - 1629
(2007/10/03)
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- Synthesis of 2,6-dimethyltropone - A new, convenient methodology from 2,6-dimethylcyclohexanone
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Until now, 2,6-dialkyltropones have not been described. 2,6-Dimethyltropone (5) represents an appropriate material for synthesis of naturally occurring antiviral compounds. A new, convenient method for synthesis of 2,6-dimethyltropone (5) from 2,6-dimethy
- Almassy, Ambroz,Pazicky, Marek,Bohac, Andrej,Salisova, Marta,Addova, Gabriela,Rosenblum, Myron
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p. 1695 - 1700
(2007/10/03)
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- A Total Synthesis of the Sesquiterpene Quinone Metachromin-A
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The first total synthesis of the marine natural product metachromin A was accomplished through a convergent synthesis amenable to the preparation of synthetic analogues.The main features of this synthesis are the introduction the oxygenation at C17 employing a Thiele acetoxylation reaction and a stereoselective Horner-Wadsworth-Emmons coupling of a nonstabilized phosphonate with a methyl ketone derivative to generate the required (E)-trisubstituted double bond.
- Almeida, Wanda P.,Correia, Carlos Roque D.
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p. 1367 - 1370
(2007/10/02)
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- 1,5-DICARBONYL COMPOUNDS A GENERAL PREPARATION METHOD
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In this report, a general method for the preparation of 1,5-dicarbonyl compounds and six membered ring annelation is described.This method involves the reaction of hemiacetal vinylogs 1 with enol ethers 2 or 3 in the presence of a Lewis acid.This reaction was successfully applied to the enol ethers of α and α,α'-hindered ketones such as 2,2,6-trimethyl cyclohexanone. α-Cyperone and 6-epi-α-cyperone were obtained using this process.
- Duhamel, P.,Hennequin, L.,Poirier, J. M.,Tavel, G.,Vottero, C.
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p. 4777 - 4786
(2007/10/02)
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- Oxidation of Enol Silyl Ethers: Preparation of Aeginetolide, Dihydroactinidiolide, and Actinidiolide
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The preparation of the C11-terpenic lactones aeginetolide (1), dihydroactinidiolide (2), and actinidiolide (3) by using 1,3,3-trimethyl-2-(trimethylsiloxy)cyclohexene (9) as a common precursor is discussed.The key steps in the synthetic route involve the sequential m-chloroperbenzoic acid (MCPBA) oxidation and acetylation of 9 and of the siloxy diene 13 derived from 9.
- Rubottom, George M.,Juve, Henrik D.
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p. 422 - 425
(2007/10/02)
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- Tertiobutylation de quelques cetones alicycliques et aliphatiques via leurs ethers d'enol trimethylsilyliques. Influence de l'environnement du carbonyle sur le deroulement de la reaction
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α-Tertiobutylation of aliphatic ketones via their trimethylsilyl enol ethers has been extended to the alicyclic series.A comparative study of the alkylation of ketones in both series with identical steric hindrance has been undertaken.The efficiency and limits of the reaction have been determinated by progressive substitution α and α' to the carbonyl.
- Lion, Claude,Dubois, Jacques-Emile
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p. 375 - 379
(2007/10/02)
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- α-Nitro Ketones. 6. Synthesis and Conformation of 2-Methyl-2-nitro-, cis- and trans-6-Methyl-2-nitro-, and cis- and trans-2,6-Dimethyl-2-nitrocyclohexanones
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Nitration of the most substituted (thermodynamically more stable) enol acetate or trimethylsilyl ether of 2-methylcyclohexanone and the phase-transfer methylation of 2-nitrocyclohexanone serve as methods of preparation of 2-methyl-2-nitrocyclohexanone, whereas nitration of the least substituted enol acetate or trimethylsilyl ether of 2-methylcyclohexanone and methylation of the dianion of 2-nitrocyclohexanone lead to cis- and trans-6-methyl-2-nitrocyclohexanone.Nitration of the enol acetate or trimethylsilyl ether of 2,6-dimethylcyclohexanone and methylation of either2-methyl-2-nitro- or 6-methyl-2-nitrocyclohexanone are methods of preparation of cis- and trans-2,6-dimethyl-2-nitrocyclohexanone. 1H NMR chemical shift and coupling constant data were used to determine the preferred conformations of the cyclohexanones: 2(e)-methyl-2(a)-nitro, cis-6(e)-methyl-2(e)-nitro, trans-6(e)-methyl-2(a)-nitro, cis-2(e),6(e)-dimethyl-2(a)-nitro, trans-2(a)-methyl-6(e)-methyl-2(e)-nitro.
- Dampawan, Pimchit,Zajac, Walter W.
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p. 1176 - 1181
(2007/10/02)
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