- Metal-Free Oxidative Decarbonylative [3+2] Annulation of Terminal Alkynes with Tertiary Alkyl Aldehydes toward Cyclopentenes
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A new metal-free oxidative decarbonylative [3+2] annulation of terminal alkynes with tertiary alkyl aldehydes is presented, which features broad substrate scope and excellent selectivity. The selectivity of this reaction toward cyclopentenes and indenes relies on the nature of the aldehyde substrates. While treatment of tertiary γ,δ-unsaturated aldehydes with common terminal alkynes assembles cyclopentenes, 2-methyl-2-arylpropanals succeed in accessing indenes.
- Zou, Hua-Xu,Li, Yang,Yang, Xu-Heng,Xiang, Jiannan,Li, Jin-Heng
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Read Online
- Rhodium-Catalyzed Tandem Isomerization-Allylation: From Diallyl Carbonates to α-Quaternary Aldehydes
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We report a Rh-catalyzed tandem isomerization-allylation sequence for the generation of α-quaternary aldehydes, starting from unsymmetrical diallyl carbonates. This reaction features a highly selective oxidative addition of the rhodium catalyst, leading to the discrimination of electrophilic and nucleophilic elements of various diallyl carbonates. A rhodium-enolate and an allyl electrophile are produced catalytically in situ in a controlled fashion, enabling this reaction to occur with high chemoselectivity and regioselectivity. Mechanistic investigation via reaction progress kinetic analysis uncovered second-order kinetics in rhodium, suggesting that an unexpected dual metal pathway may be operative for the key C-C bond-forming step.
- Masson-Makdissi, Jeanne,Jang, Young Jin,Prieto, Liher,Taylor, Mark S.,Lautens, Mark
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p. 11808 - 11812
(2019/12/02)
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- Nickel-Catalyzed α-Allylation of Aldehydes and Tandem Aldol Condensation/Allylation Reaction with Allylic Alcohols
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An additive-free nickel-catalyzed α-allylation of aldehydes with allyl alcohol is reported. The reaction is promoted by 1 mol % of in situ formed nickel complex in methanol, and water is the sole by-product of the reaction. The experimental conditions allow the conversion of various α-branched aldehydes and α,β-unsaturated aldehydes as nucleophiles. The same catalyst and reaction conditions enabled a tandem aldol condensation of aldehyde/α-allylation reaction.
- Bernhard, Yann,Thomson, Brodie,Ferey, Vincent,Sauthier, Mathieu
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supporting information
p. 7460 - 7464
(2017/06/13)
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- Isomerization of olefins triggered by rhodium-catalyzed C-H bond activation: Control of endocyclic β-hydrogen elimination
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Five-membered metallacycles are typically reluctant to undergo endocyclic β-hydrogen elimination. The rhodium-catalyzed isomerization of 4-pentenals into 3-pentenals occurs through this elementary step and cleavage of two C-H bonds, as supported by deuterium-labeling studies. The reaction proceeds without decarbonylation, leads to trans olefins exclusively, and tolerates other olefins normally prone to isomerization. Endocyclic β-hydrogen elimination can also be controlled in an enantiodivergent reaction on a racemic mixture.
- Yip, Stephanie Y. Y.,A?ssa, Christophe
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p. 6870 - 6873
(2015/06/02)
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- Activation of alcohols with carbon dioxide: Intermolecular allylation of weakly acidic pronucleophiles
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The direct coupling of allyl alcohols with nitroalkanes, nitriles, and aldehydes using catalytic Pd(PPh3)4 has been accomplished via activation of C-OH bonds with CO2. The in situ formation of carbonates from alcohols and CO2 facilitates oxidative addition to Pd to form reactive π-allylpalladium intermediates. In addition, the formation of a strong base activates nucleophiles toward the reaction with the π-allylpalladium electrophile. Overall, this atom economical reaction provides a new C-C bond without the use of an external base and generates water as the only byproduct.
- Lang, Simon B.,Locascio, Theresa M.,Tunge, Jon A.
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supporting information
p. 4308 - 4311
(2014/11/08)
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- Asymmetric α-allylation of α-branched aldehydes with allyl alcohols by synergistic catalysis using an achiral palladium complex and a chiral primary amino acid
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Highly enantioselective direct α-allylation of α-branched aldehydes with simple allyl alcohols was achieved by the combined use of an achiral transition-metal catalysis with a palladium complex and a chiral organocatalysis with a readily obtainable primary α-amino acid. Various α-allylated aldehydes possessing a stereocontrolled quaternary carbon stereogenic center were synthesized in high yields with high enantioselectivity. Georg Thieme Verlag Stuttgart New York.
- Yoshida, Masanori,Masaki, Erika,Terumine, Tatsuaki,Hara, Shoji
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p. 1367 - 1373
(2014/06/09)
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- Palladium/Bronsted acid-catalyzed α-allylation of aldehydes with allylic alcohols
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A simple, highly efficient, and readily scalable direct α-allylation of aldehydes with allylic alcohols that is co-catalyzed by palladium and a Bronsted acid has been developed. Copyright
- Jiang, Gaoxi,List, Benjamin
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experimental part
p. 1667 - 1670
(2011/09/14)
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- Pd-catalyzed α-allylation of 2-phenylpropanal and other carbonyl compounds with allyl alcohol and allyl acetates/carbonates in ionic liquids
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The successful Pd-catalysed allylation of 2-phenylpropanal with allyl alcohol in ionic liquid is described and thus a simplier reaction composition catalytic system than in THF is possible. On the other hand, the Pd-catalyzed α-allylation of the same substrate with allyl acetate or allyl ethyl carbonate is proceeding nicely in ionic liquids. Allylation of different carbonyl derivatives was studied and it was found that the reaction is restricted to carbonyl derivatives from which a carbanion stabilized by an adjacent aromatic ring can be formed.
- Hut'Ka, Martin,Toma, Stefan
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p. 1175 - 1179
(2008/03/27)
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- 1,1,1-TRIFLUORO-4-PHENYL-4-METHYL-2-(1H-PYRROLO
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Compounds of Formula (IA), IB), IC), and (ID) wherein R1, R2, R3, R4, R5, and R6 are as respectively defined herein for Formula (IA), (IB), (IC), and (ID), or a tautomer, prodrug, solvate, or salt thereof; pharmaceutical compositions containing such compounds, and methods of modulating the glucocorticoid receptor function and methods of treating disease-states or conditions mediated by the glucocorticoid receptor function or characterized by inflammatory, allergic, or proliferative processes in a patient using these compounds.
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Page/Page column 211
(2010/02/11)
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- Chemokine receptor binding heterocyclic compounds with enhanced efficacy
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The invention relates to heterocyclic compounds consisting of a core nitrogen atom surrounded by three pendant groups, wherein two of the three pendant groups are preferably benzimidazolyl methyl and tetrahydroquinolyl, and the third pendant group contains N and optionally contains additional rings. The compounds bind to chemokine receptors, including CXCR4 and CCR5, and demonstrate protective effects against infection of target cells by a human immunodeficiency virus (HIV).
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- An expedient protocol for cyclopentenone annulation
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A convenient and general protocol for the cyclopentenone annulation process is described.
- Kulkarni, Mukund G.,Davawala, Saryu I.,Doke, Aniruddha K.,Pendharkar, Dhananjay S.
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p. 2919 - 2926
(2007/10/03)
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- Chemokine receptor binding heterocyclic compounds with enhanced efficacy
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The invention relates to heterocyclic compounds consisting of a core nitrogen atom surrounded by three pendant groups, wherein two of the three pendant groups are preferably benzimidazolyl methyl and tetrahydroquinolyl, and the third pendant group contains N and optionally contains additional rings. The compounds bind to chemokine receptors, including CXCR4 and CCR5, and demonstrate protective effects against infection of target cells by a human immunodeficiency virus (HIV).
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Page/Page column 43-45
(2010/02/03)
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- Design, synthesis, and SAR of heterocycle-containing antagonists of the human CCR5 receptor for the treatment of HIV-1 infection
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Replacement of the large hydantoin-indole moiety from our previous work with a variety of smaller heterocyclic analogues gave rise to potent CCR5 antagonists having binding affinity comparable to the hydantoin analogues. The synthesis, SAR, and biological profiles of this class of antagonists are described.
- Kim, Dooseop,Wang, Liping,Caldwell, Charles G.,Chen, Ping,Finke, Paul E.,Oates, Bryan,MacCoss, Malcolm,Mills, Sander G.,Malkowitz, Lorraine,Gould, Sandra L.,DeMartino, Julie A.,Springer, Martin S.,Hazuda, Daria,Miller, Michael,Kessler, Joseph,Danzeisen, Renee,Carver, Gwen,Carella, Anthony,Holmes, Karen,Lineberger, Janet,Schleif, William A.,Emini, Emilio A.
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p. 3103 - 3106
(2007/10/03)
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- Rhodium promoted isomerisation of allylic alkoxides: A new method for enolate anion formation
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Transition metal mediated isomerisation of allylic alkoxides is presented as a new method for enolate anion generation. The scope and limitations of enolate formation with the catalysts [Rh(dppe)(THF)2]+ClO4- and (Ph3P)3RhCl are explored and the synthetic potential of the methodology demonstrated in the stereoselective formation and reactions of certain ketone and aldehyde enolates.
- Gazzard, Lewis J.,Motherwell, William B.,Sandham, David A.
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p. 979 - 993
(2007/10/03)
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- Reverse Cope Elimination Reactions. 1. Mechanism and Scope
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N-4-Pentenyl- and N-5-hexenyl-N-methylhydroxylamine cyclized under mild conditions in a reverse Cope elimination reaction to give 1,2-dimethylpyrrolidine N-oxide and 1,2-dimethylpiperidine N-oxide, respectively.The reaction was shown to be concerted and thermodynamically controlled.The scope of this novel cyclization is discussed, and comparisons are made with the closely related and previously reported cyclization of monosubstituted alkenylhydroxylamines to give cyclic hydroxylamines.
- Ciganek, Engelbert,Read, John M.,Calabrese, Joseph C.
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p. 5795 - 5802
(2007/10/03)
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- Palladium(0)-Catalyzed Rearrangement of N-Allylenamines. Synthesis of δ,ε-Unsaturated Imines and γ,δ-Unsaturated Carbonyl Compounds
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Palladium-catalyzed rearrangement of N-allylenamines proceeds readily in the presence of a catalytic amount of trifluoroacetic acid to give δ,ε-unsaturated imines.Conveniently, δ,ε-unsaturated imines can be prepared directly by the reaction of allylamines with carbonyl compounds under the same conditions highly efficiently.The reaction involves oxidative addition of Pd(0) species to allylenammonium salts to give ?-allylpalladium complexes, which undergo intramolecular nucleophilic reaction with enamines give imines.The δ,ε-unsaturated imines are versatile synthetic precursors such as γ,δ-unsaturated carbonyl compounds.Synthetic applications are also described.
- Murahashi, Shun-Ichi,Makabe, Yoshiki,Kunita, Kazuto
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p. 4489 - 4495
(2007/10/02)
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- CATALYTIC DECARBONYLATION, HYDROACYLATION, AND RESOLUTION OF RACEMIC PENT-4-ENALS USING CHIRAL BIS(DITERTIARY-PHOSPHINE) COMPLEXES OF RHODIUM(I)
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Attempts to decarbonylate racemic aldehydes catalytically using rhodium(I) complexes containing chiral di-tertiary-phosphine ligands are described.Incorporation of an alkenic moiety into the aldehyde, for subsequent probing of induced asymmetry by chiral shift reagents, leads instead to formation of optically active hydroacylated products via kinetic resolution of the precursor racemic aldehyde.For example, (RS)-2-methyl-2-phenylpent-4-enal (1a) yields, on treatment with Cl, 2-methyl-2-phenylcyclopentanone with up to 69percent e.e of the (-)-(S) optical isomer and remaining unreacted aldehyde which is possibly the enantiomerically pure (-)-(R) form.Extension of this cyclization reaction to a 3,3-disubstituted pent-4-enal similarly provides a synthesis for an optically active 3,3-disubstituted cyclopentanone.Decarbonylation by-products are also observed; those from 1a appear as E- and Z-2-phenylpent-2-ene.The cyclization of 1a is catalyzed also by Rh(chiraphos)(solvent)2+ but with lower e.e.
- James, Brian R.,Young, Charles G.
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p. 321 - 332
(2007/10/02)
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- PALLADIUM(0) CATALYZED 3-AZA-COPE REARRANGEMENT OF N-ALLYLENAMINES
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Pd(0) complexes catalyze the 3-Aza-Cope rearrangement of N-allylenamines to the corresponding δ,ε-unsaturated imines or γ,δ-unsaturated carbonyl compounds in the presence of trifluoroacetic acid as co-catalyst.
- Murahashi, Shun-Ichi,Makabe, Yoshiki
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p. 5563 - 5566
(2007/10/02)
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- DIALKYLTELLURONIUM ALLYLIDE AS A NOVEL REAGENT FOR SYNTHESIS OF Α,Β-UNSATURATED EPOXIDES
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Reaction of dialkyltelluronium allylide with aldehydes gave rise to α,β-unsatirated epoxides with moderate Z-selectivity and in good yields.
- Osuka, Atsuhiro,Suzuki, Hitomi
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p. 5109 - 5112
(2007/10/02)
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- Geminal Acylation-Alkylation at a Carbonyl Carbon via Regiospecifically Generated Metalloenamines
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A useful procedure for effecting geminal disubstitution at the carbonyl carbon atom of aldehydes and ketones has been developed in which the sequence of reactions results in the replacement of the two carbon-oxygen bonds of the carbonyl function with an acyl group and an alkyl or hydroxyalkyl group.Of particular importance is the facile application of these procedures to the efficient construction of quaternary carbon atoms that bear alkyl appendages containing differentiated functionality.This novel methodology features the initial conversion of carbonyl compounds 1 into the substituted 2-azadienes 10 or 11 by Wittig-Horner reaction.Subsequent reaction of these 2-azadienes produced in situ with n-butyllithium results in the formation of the metalloenamines 12 and 13 (R4 = n-Bu) which undergo reactions with a wide variety of electrophiles to give, after hydrolysis of the intermediate imines, the α-substituted aldehydes 14 or the α-substituted ketones 15 in good of excellent overall yields.New procedures for the annelation of cyclopentenones such as 22 and cyclohexenones 26 at the carbonyl carbon of ketones are described as is an important variant of a directed aldol reaction, 1 --> 28.Although a number of individual manipulations are necessary to effect the geminal disubstitution of a carbonyl functional group, it is generally feasible to execute the entire sequence of reactions in single flask, thereby rendering this methodology very convenient to implement in practice.
- Martin, Stephen F.,Phillips, Gerald W.,Puckette, Thomas A.,Colapret, John A.
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p. 5866 - 5872
(2007/10/02)
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