- Catalytic asymmetric allylation of ketones and a tandem asymmetric allylation/diastereoselective epoxidation of cyclic enones
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A simple procedure is reported for the catalytic asymmetric allylation of ketones, utilizing titanium tetraisopropoxide, BINOL, 2-propanol additive, and tetraallylstannane as allylating agent. A variety of ketone substrates, including acetophenone derivat
- Kim, Jeung Gon,Waltz, Karen M.,Garcia, Iliana F.,Kwiatkowski, David,Walsh, Patrick J.
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- Hydroxy chalcogenide-promoted Morita-Baylis-Hillman Alkylation reaction: Intermolecular applications with alkyl halides as electrophiles
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Hydroxysulfides acted as catalysts to promote the Morita-Baylis-Hillman alkylation reaction of cyclohexenones and dihydropyridinones. The procedure worked efficiently with a variety of halides as electrophiles. Side reactions were in competition with the MBH alkylation, but fine-tuning the reaction conditions minimized their occurence.
- Gradillas, Ana,Belmonte, Efres,Da Silva, Rondes Ferreira,Perez-Castells, Javier
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p. 1935 - 1941
(2014/04/03)
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- Hydroxy Chalcogenide-Promoted Morita-Baylis-Hillman Alkylation Reaction: Intermolecular Applications with Alkyl Halides as Electrophiles
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Hydroxysulfides acted as catalysts to promote the Morita-Baylis-Hillman alkylation reaction of cyclohexenones and dihydropyridinones. The procedure worked efficiently with a variety of halides as electrophiles. Side reactions were in competition with the
- Gradillas, Ana,Belmonte, Efres,Da Silva, Rondes Ferreira,Prez-Castells, Javier
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p. 1935 - 1941
(2015/10/05)
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- An efficient method for construction of the angularly fused 6,3,5-tricyclic skeleton of mycorrhizin A and its analogues
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(Chemical Equation Presented) The angularly fused 6,3,5-tricyclic system is readily generated via a cascade cyclization under acid promotion. The reaction proceeds at room temperature with high stereochemical fidelity from the electrophilic center of the
- Yu, Binxun,Jiang, Tuo,Quan, Weiguo,Li, Junpeng,Pan, Xinfu,She, Xuegong
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supporting information; experimental part
p. 629 - 632
(2009/07/25)
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- METHOD FOR MAKING BIARYL COMPOUNDS, COMPOUNDS MADE BY THE METHOD, AND METHOD FOR THEIR USE
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Certain disclosed embodiments of the present invention concern a method for making biaryl compounds by combining a diene with a dienophile under reaction conditions that facilitate a Diels-Alder reaction. Certain embodiments are particularly directed to making a tetra-ortho-substituted biaryl compounds. The disclosed method may involve using novel dienes, dienophiles, or both. Similarly, certain of the biaryl compounds are novel compounds too. Additional disclosed embodiments concern a method for making useful compounds by first making a Diels-Alder adduct. The Diels-Alder adduct is then further modified or coupled to other compounds. The method can be used to make carbazoles, such as Siamenol. Disclosed biaryl compounds are useful for a number of applications, such as pharmacophores and organocatalysts.
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Page/Page column 91-92
(2009/01/23)
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- Divergent enantioselective synthesis of (-)-galanthamine and (-)-morphine
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An efficient divergent synthetic strategy for the synthesis of the opiate and amaryllidaceae alkaloids emerges by employing a Pd-catalyzed asymmetric allylic alkylation (AAA) to set the stereochemistry. Three generations of syntheses of galanthamine are discussed in detail with particular focus on the scope of the palladium-catalyzed AAA reactions and intramolecular Heck reactions. The pivotal tricyclic intermediate is available in six steps from 2-bromovanillin and the monoester of methyl 6-hydroxycyclohexene-1-carboxylate. This intermediate requires only two steps to convert to (-)-galanthamine. Using a Heck vinylation, we found that the fourth ring of codeine/morphine could be formed. The final ring formation involves a novel visible light-promoted hydroamination. Thus, six steps are required to convert the pivotal tricyclic intermediate into codeine, which has been demethylated in high yield to morphine.
- Trost, Barry M.,Tang, Weiping,Toste, F. Dean
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p. 14785 - 14803
(2007/10/03)
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- Tetrathiafulvalene-mediated stereoselective synthesis of the tetracyclic core of Aspidosperma alkaloids
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A novel route to advanced synthetic precursors of Aspidosperma alkaloids is described, utilising radical-polar crossover reactions.
- Fletcher, Rodney,Kizil, Murat,Lampard, Christopher,Murphy, John A.,Roome, Stephen J.
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p. 2341 - 2351
(2007/10/03)
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- Mn(III)-based oxidative free-radical cyclizations of unsaturated ketones
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Mn(III)-based oxidative free-radical cyclization of unsaturated ketones is a versatile synthetic procedure with broad applicability. For example, oxidation of cyclopentanone 1a with 2 equiv of Mn(OAc)3·2H2O and 1 equiv of Cu(OAc)sub
- McCarthy Cole, Bridget,Han, Luning,Snider, Barry B.
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p. 7832 - 7847
(2007/10/03)
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- Stereocontrolled synthesis of complex polycycles using tetrathiafulvalene mediated radical-polar crossover reactions
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Tetracyclic heterocycles are prepared in a stereocontrolled manner using radical-polar crossover chemistry.
- Fletcher, Rodney J.,Hibbs,Hursthouse,Lampard, Christopher,Murphy, John A.,Roome, Stephen J.
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p. 739 - 740
(2007/10/03)
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- SYNTHESES DE CYCLOHEXENONES α-SUBSTITUEES VIA LA THERMOLYSE DE CETOSULFOXYDES TERTIAIRES
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The sulfenylation-dehydrosulfenylation method, combined with carbon-carbon bond forming reactions, has been applied to the synthesis of some α-functionalized cyclohexenones 3.Hence, the sodium anion of the 2-methylthiocyclohexanone in THF reacts with primary, allyl and benzyl halides as well as with Michael acceptors to lead to the tertiary ketosulfides 1a-j.Further oxidation by NaIO4 and thermolysis in boiling toluene of the resulting sulfoxides 2 have been performed.The scope and limitations of this strategy are also discussed. Key Words: α-functionalized cyclohexenones; tertiary ketosulfides and ketosulfoxides; sulfenylation and deshydrosulfenylation; thermolysis.
- Barillier, Daniel,Benhida, Rachid,Vazeux, Michel
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- A Novel Vinyl Anion Equivalent. An Extremely Short Synthesis of 2-Substituted 2-Cycloalkenones and Prostaglandin Key Intermediates via Destannylselenenylation
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The preparation of a novel vinyl anion equivalent and a new destannylselenenylation procedure are described.The conjugate addition of (tributylstannyl)lithium to 2-(phenylseleno)-2-cycloalkenones, followed by the trapping of the resulting enolates with al
- Kusuda, Shinya,Watanabe, Yoshihiko,Ueno, Yoshio,Toru, Takeshi
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p. 3145 - 3152
(2007/10/02)
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- 2,3a,5,6,7,7a-HEXAHYDRO-3H,4H-BENZOTHIOPHENE-3,4-DIONE AND CYCLOPENTA-TETRAHYDROTHIOPHENE-3,4-DIONE ENOLATE ANIONS AS SYNTHETIC EQUIVALENTS TO CYCLOHEX-2-ENONE AND CYCLOPENT-2-ENONE C-2-CARBANIONS.
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An efficient procedure for α-alkylation of cyclohex-2-enone and cyclopent-2-enone involving a base-promoted tandem of retrograde Dieckmann-Michael reactions of the C-alkylated derivatives of the title heterocycles is presented.
- Baraldi, Pier Giovanni,Barco, Achille,Benetti, Simonetta,Pollini, Gian Piero,Zanirato, Vinicio
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p. 4291 - 4294
(2007/10/02)
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