- Conversion of an amine-substituted amine-manganese tricarbonyl complex to a functionalized cyclohexenone
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The synthesis of functionalized cyclohexenones can be achieved via double nucleophile addition, with intermediate reactivation by ligand exchange, to aminoarene-manganese tricarbonyl cationic complexes by adjusting the electron donating power of the amine.
- Pearson, Anthony J.,Vickerman, Richard J.
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- Enantioselective Synthesis of γ-Functionalized Cyclopentenones and δ-Functionalized Cycloheptenones Utilizing a Redox-Relay Heck Strategy
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In this report, the desymmetrization of cyclic enones under relay Heck conditions with an array of aryl boronic acids, alkenyl triflates and indole derivatives is described. This method grants facile access to diverse γ-functionalized cyclopentenones and δ-functionalized cycloheptenones. Using this approach, a formal synthesis of (S)-baclofen was completed in high yield and excellent enantioselectivity. (Figure presented.).
- Yuan, Qianjia,Prater, Matthew B.,Sigman, Matthew S.
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supporting information
p. 326 - 330
(2019/11/14)
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- CeO2-Supported Pd(II)-on-Au Nanoparticle Catalyst for Aerobic Selective α,β-Desaturation of Carbonyl Compounds Applicable to Cyclohexanones
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Direct selective desaturation of carbonyl compounds to synthesize α,β-unsaturated carbonyl compounds represents an environmentally benign alternative to classical stepwise procedures. In this study, we designed an ideal CeO2-supported Pd(II)-on-Au nanoparticle catalyst (Pd/Au/CeO2) and successfully achieved heterogeneously catalyzed selective desaturation of cyclohexanones to cyclohexenones using O2 in air as the oxidant. Besides cyclohexenones, various bioactive enones can also be synthesized from the corresponding saturated ketones under open air conditions in the presence of Pd/Au/CeO2. Preliminary mechanistic studies revealed that α-C-H bond cleavage in the substrates is the turnover-limiting step of this desaturation reaction.
- Jin, Xiongjie,Mizuno, Noritaka,Takei, Daisuke,Yabe, Tomohiro,Yamaguchi, Kazuya,Yatabe, Takafumi
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p. 5057 - 5063
(2020/05/27)
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- Metal-Free I2-Catalyzed Highly Selective Dehydrogenative Coupling of Alcohols and Cyclohexenones
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The I2 catalyzed highly selective oxidative condensation of cyclohexenones and alcohols for the synthesis of aryl alkyl ethers has been described. DMSO is employed as the mild terminal oxidant. This novel methodology offers a metal-free reaction condition, operational simplicity and broad substrate scope to afford valuable products from inexpensive reagents. Various meta-substituted aromatic ethers which are hardly synthesized from the reported methods requiring meta-substituted phenols, are efficiently prepared by the present protocol.
- Liang, Yu-Feng,Yuan, Yizhi,Shen, Tao,Song, Song,Jiao, Ning
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supporting information
p. 233 - 240
(2018/02/19)
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- Iodine-Promoted Semmler–Wolff Reactions: Step-Economic Access to meta-Substituted Primary Anilines via Aromatization
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An atom- and step-economic access to an array of unprotected meta-substituted primary anilines was disclosed using the Semmler–Wolff reaction, promoted by molecular iodine. Therein, noble metal catalysts and inert atmosphere are unnecessary while the forcing reaction conditions and the lengthy synthesis can be avoided. The synthetic utility of this approach is evident in the de novo syntheses of three bioactive molecules with good total yields.
- Wang, Shi-Ke,You, Xia,Zhao, Da-Yuan,Mou, Neng-Jie,Luo, Qun-Li
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p. 11757 - 11760
(2017/09/07)
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- Experimental studies on the selective β-c-h halogenation of enones
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Here we describe the realization of a one-pot protocol for the β-C-H halogenation of cyclic enones via umpolung of the β-carbon. The developed method includes hydrazone formation and selective β-halogenation (bromination, chlorination) with N-bromosuccini
- Huber, Tatjana,Kaiser, Daniel,Rickmeier, Jens,Magauer, Thomas
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p. 2281 - 2294
(2015/03/18)
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- Catalytic Enantioselective Nitroso Diels-Alder Reaction
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The nitroso Diels-Alder (NDA) reaction is an attractive strategy for the synthesis of 3,6-dihydro-1,2-oxazines and 1-amino-4-hydroxy-2-ene derivatives. Herein we report the Cu(I)-DTBM-Segphos catalyzed asymmetric intermolecular NDA reaction of variously substituted cyclic 1,3-dienes using highly reactive nitroso compounds derived from pyrimidine and pyridazine derivatives. In most of the cases studied, the cycloadducts were obtained in high yields (up to 99%) with very high regio-, diastereo-, and enantioselectivities (up to regioselectivity > 99:1, d.r. > 99:1, and >99% ee). As an application of this methodology, formal syntheses of conduramine A-1 and narciclasine were accomplished.
- Maji, Biplab,Yamamoto, Hisashi
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p. 15957 - 15963
(2016/01/09)
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- Silver(I)-catalyzed ring-contractive rearrangement: A new entry to 5-alkylidene-2-cyclopentenones
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A novel silver(I)-catalyzed ring-contractive rearrangement of 5-substituted 6-diazo-2-cyclohexenones has been developed, providing a new and efficient access to 5-alkylidene-2-cyclopentenones. The AgOTf-catalyzed reaction proceeds through metal-carbenoid formation followed by endocyclic allyl [1,2] migration with excellent stereoselectivity and broad substrate scope.
- Zhao, Liang,Wang, Jinlian,Zheng, Hongyan,Li, Yun,Yang, Ke,Cheng, Bin,Jin, Xiaojie,Yao, Xiaojun,Zhai, Hongbin
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supporting information
p. 6378 - 6381
(2015/01/09)
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- Hydroxy-rhodium(I) catalyzed regioselective Michael addition of cyclic enones
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Hydroxy-rhodium catalyzed dimerization of various cyclic enones to the corresponding α-enone adducts is developed. The key feature of this method is that the base-sensitive, highly substituted enones also undergo dimerization and the resultant products ar
- Kumaraswamy, Gullapalli,Rambabu, Dasa
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supporting information; scheme or table
p. 1042 - 1044
(2012/03/26)
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- Synthesis of cyclic enones via direct palladium-catalyzed aerobic dehydrogenation of ketones
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α,β-Unsaturated carbonyl compounds are versatile intermediates in the synthesis of pharmaceuticals and biologically active compounds. Here, we report the discovery and application of Pd(DMSO)2(TFA)2 as a catalyst for direct dehydrogenation of cyclohexanones and other cyclic ketones to the corresponding enones, using O2 as the oxidant. The substrate scope includes heterocyclic ketones and several natural-product precursors.
- Diao, Tianning,Stahl, Shannon S.
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supporting information; experimental part
p. 14566 - 14569
(2011/10/17)
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- Catalytic enantioselective conjugate allylation of unsaturated methylidene ketones
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The use of unsaturated methylidene ketones in catalytic conjugate allylations allows a significant expansion in substrate scope and, with appropriate chiral ligands, occurs in a highly enantioselective fashion.(Figure Presented)
- Brozek, Laura A.,Sieber, Joshua D.,Morken, James P.
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p. 995 - 997
(2011/05/15)
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- Palladium-catalyzed decarboxylative asymmetric allylic alkylation of enol carbonates
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Palladium-catalyzed decarboxylative asymmetric allylic alkylation (DAAA) of allyl enol carbonates as a highly chemo-, regio-, and enantioselective process for the synthesis of ketones bearing either a quaternary or a tertiary R-stereogenic center has been investigated in detail. Chiral ligand L4 was found to be optimal in the DAAA of a broad scope of cyclic and acyclic ketones including simple aliphatic ketones with more than one enolizable proton. The allyl moiety of the carbonates has been extended to a variety of cyclic or acyclic disubstituted allyl groups. Our mechanistic studies reveal that, similar to the direct allylation of lithium enolates, the DAAA reaction proceeds through an "outer sphere" S N2 type of attack on the π-allylpalladium complex by the enolate. An important difference between the DAAA reaction and the direct allylation of lithium enolates is that in the DAAA reaction, the nucleophile and the electrophile were generated simultaneously. Since the π-allylpalladium cation must serve as the counterion for the enolate, the enolate probably exists as a tight-ion-pair. This largely prevents the common side reactions of enolates associated with the equilibrium between different enolates. The much milder reaction conditions as well as the much broader substrate scope also represent the advantages of the DAAA reaction over the direct allylation of preformed metal enolates.
- Trost, Barry M.,Xu, Jiayi,Schmidt, Thomas
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supporting information; experimental part
p. 18343 - 18357
(2010/04/25)
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- Catalytic conjugate addition of allyl groups to styryl-activated enones
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Conjugate addition of pinacolato(allyl)boron to benzylidenealkylidene ketones is remarkably facile when catalyzed by Ni(0) and Pd(0) complexes. Simple enones are inert to the reaction conditions, suggesting a significant activating effect by the auxiliary benzylidene unit. A comparison of different catalysts and substrates is provided, as is a mechanistic rationale, and an example of asymmetric catalysis. Copyright
- Sieber, Joshua D.,Liu, Shubin,Morken, James P.
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p. 2214 - 2215
(2007/10/03)
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- Investigation of the aqueous transmetalation of π-allylpalladium with indium salt: The use of the Pd(OAc)2-TPPTS catalyst
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π-Allylpalladium complexes could be generated in water by the palladium(0) water soluble catalyst prepared in situ from palladium acetate and TPPTS. These complexes were transmetalated with indium to react with benzaldehyde. The aqueous solution of Pd(0)(TPPTS)n could be reused without deterioration of the catalyst in the first and second recycling. The system proved to be efficient with primary and secondary allylic substrates. The stereochemical outcome of the allylation through umpolung of allylpalladium, was also studied using models with a restraint conformation. The Royal Society of Chemistry 2005.
- Fontana, Gianfranco,Lubineau, Andre,Scherrmann, Marie-Christine
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p. 1375 - 1380
(2007/10/03)
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- Stereocontrol in a one-pot procedure for anionic oxy-Cope rearrangement followed by intramolecular aldol reaction
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Racemic β-hydroxycyclohexanones with up to three chiral centres have been synthesized in a stereocontrolled way using the novel anionic oxy-Cope (AOC) rearrangement of acyclic enol ethers. The first examples of compounds containing an aldehyde and an enol ether in a 1,5 relationship are reported. Stereocontrol in the cyclisation of these compounds by a 6-(enolendo)-exo-trig intramolecular aldol reaction has been studied: there is high stereoselectivity for an axial hydroxy group in the product β-hydroxycyclohexanones. AM1 calculations show that there is a stabilising electrostatic attraction between the oxygen atom of the axial C-3 hydroxy group and the electron-poor carbon at C-1 in the intermediate oxonium ions. ≥87% of AOC rearrangement occurs via a chair-like transition state giving rise to the 5,6-anti stereochemistry of the β-hydroxycyclohexanones. Trapping the enolate product of AOC rearrangement with oxygen gives fragmentation via a 1,2-dioxetane.
- Rutherford, Alistair P.,Gibb, Cameron S.,Hartley, Richard C.,Goodman, Jonathan M.
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p. 1051 - 1061
(2007/10/03)
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- Dienediolates of Unsaturated Carboxylic Acids in Synthesis. Synthesis of Cyclohexenones and Polycyclic Ketones by Tandem Michael-Dieckmann Decarboxylative Annulation of Unsaturated Carboxylic Acids.
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Substituted 2-cyclohexenones 4 to 7 and hexahydronaphthalenones and hexahydroindenones 13 to 18 are prepared by tandem Michael-Dieckmann addition of lithium dienediolates of acyclic and alicyclic unsaturated carboxylic acids to the lithium salts of the same or other unsaturated carboxylic acids.
- Aurell, Maria J.,Gavina, Pablo,Mestres, Ramon
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p. 2571 - 2582
(2007/10/02)
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- Reaction of organolithium reagents with η5-pentadienyl iron complexes: Formation of σ,η3-iron complexes
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Reaction of organolithium reagents with η5-pentadienyl iron complex 4 occurs at the C2/C4 position of the π-system, generating σ,η3-iron complexes 5. Air oxidation of these σ,η3-iron complexes generates cyclohexenones. Rea
- McDaniel, Keith F.,Kracker II, Larry R.,Thamburaj, Parinbam K.
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p. 2373 - 2376
(2007/10/02)
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- Synthesis of Chiral 5-Substituted Cyclohex-2-enones from 5-Trimethylsilylcyclohex-2-enone
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Optically active and racemic-5-substituted cyclohex-2-enones were synthesized from 5-trimethylsilylcyclohex-2-enone.
- Asaoka, Morio,Shima, Kunihisa,Takei, Hisashi
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p. 430 - 431
(2007/10/02)
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- Observations sur l'hydrolyse d'acetals dihydropyranniques
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The hydrolysis of of dihydropyranyl acetals by sulfuric acid leads to cyclenones, but by the use of pyridinium p-tolenesulfonate, δ-ketoaldehydes may be isolated.These compounds do not undergo aldol condensation under these conditions.
- Thuy, Vu Moc,Maitte, Pierre
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p. 497 - 499
(2007/10/02)
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