- Aromatization as an Impetus to Harness Ketones for Metallaphotoredox-Catalyzed Benzoylation/Benzylation of (Hetero)arenes
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Herein we report ketones as feedstock materials in radical cross-coupling reactions under Ni/photoredox dual catalysis. In this approach, simple condensation first converts ketones into prearomatic intermediates that then act as activated radical sources for cross-coupling with aryl halides. Our strategy enables the direct benzylation/benzoylation of (hetero)arenes under mild reaction conditions with high functional group tolerance.
- Chen, Ting-Wei,Cheng, Cheng-Ku,Chiu, Cheng-Chau,Huang, Pin-Gong,Lee, Shao-Chi,Lee, Yi-Hsin,Li, Li-Yun,Liao, Hsuan-Hung,Lin, Heng-Bo,Tsai, Zong-Nan,Tsao, Yong-Ting,Yang, Chung-Hsin
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- EFFICIENT AND SELECTIVE ROUTE FOR THE SYNTHESIS OF ALKYL 2-BENZOYLBENZOATE
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A method for preparing an alkyl 2-benzoylbenzoate comprising reacting a dialkyl phthalate with a Grignard reagent in the presence of an oxygenated solvent. The Grignard reagent may be selected from phenyl magnesium bromide, phenyl magnesium chloride, and phenyl magnesium iodide.
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Paragraph 0028
(2021/08/27)
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- Acyl radicals from α-keto acids using a carbonyl photocatalyst: Photoredox-catalyzed synthesis of ketones
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Acyl radicals have been generated from α-keto acids using inexpensive and commercially available 2-chloro-thioxanthen-9-one as the photoredox catalyst under visible light illumination. These reactive species added to olefins or coupled with aryl halides via a bipyridylstabilized Ni(II) catalyst, enabling easy access to a diverse range of ketones. This reliable, atom-economical, and eco-friendly protocol is compatible with a wide range of functional groups.
- Zhu, Da-Liang,Wu, Qi,Young, David James,Wang, Hao,Ren, Zhi-Gang,Li, Hong-Xi
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supporting information
p. 6832 - 6837
(2020/10/12)
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- Metal-Free Arylation-Lactonization Sequence of γ-Alkenoic Acids Using Anilines as Aryl Radical Precursors
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The presence of salicylic acid (10 mol-%) and H2O (10 equiv.) significantly improves the arylation-lactonization sequence of γ-alkenoic acids with in situ formed diazonium salts (from bench stable anilines). The reaction is finished in less than 5 h without thermal or photochemical activation, giving access to a variety of γ,γ-disubstituted butyrolactones. The protocol is user-friendly and can be used at gram-scale or adapted to transform alkenols into phthalanes. Control experiments revealed that aryl radicals participate in the reaction and a plausible mechanism is proposed to include this and other mechanistic investigations, for the catalyzed and the background reaction.
- Felipe-Blanco, Diego,Gonzalez-Gomez, Jose C.
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supporting information
p. 7735 - 7744
(2019/12/24)
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- Palladium-Catalyzed Direct Oxidative Coupling of Iodoarenes with Primary Alcohols Leading to Ketones: Application to the Synthesis of Benzofuranones and Indenones
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In the present study, a palladium-catalyzed direct oxidative acylation through cross-dehydrogenative coupling has been investigated, utilizing readily available primary alcohols as acylating sources. Overall, this oxidative coupling proceeds via three distinct transformations such as oxidation, radical formation, and cross-coupling in one catalytic process. This protocol does not involve the assistance of a directing group or activation of the carbonyl group by any other means. Furthermore, this reaction made use of no toxic CO gas as carbonylating agent; instead, feedstock primary alcohols have been utilized as acylation source. Notably, the synthesis of benzofuranones and indenones is enabled. This strategy was also applied to the synthesis of n-butylphthalide, fenofibrate, pitofenone, and neo-lignan.
- Suchand, Basuli,Sreenivasulu, Chinnabattigalla,Satyanarayana, Gedu
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p. 4832 - 4843
(2019/07/31)
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- Palladium-Catalyzed Acylation Reactions: A One-Pot Diversified Synthesis of Phthalazines, Phthalazinones and Benzoxazinones
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A sequential one-pot strategy for the diversified synthesis of phthalazines, phthalazinones and benzoxazinones was presented. This strategy proceeds through [Pd]-catalyzed acylation and nucleophilic cyclocondensation with dinucleophilic reagents. This process was based on direct coupling with simple bench-top aldehydes without the assistance of directing group and without activating the carbonyl group. The process is highly advantageous because it employs simple nitrogen-based nucleophiles, and non-toxic and readily accessible aldehydes as the carbonyl source. Most importantly, the strategy was applied to the one-pot synthesis of PDE-4 inhibitor.
- Suchand, Basuli,Satyanarayana, Gedu
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p. 2233 - 2246
(2018/06/04)
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- Ruthenium-Catalyzed Enantioselective Hydrogenation/Lactonization of 2-Acylarylcarboxylates: Direct Access to Chiral 3-Substituted Phthalides
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Highly enantioselective tandem hydrogenation/lactonization of various 2-acylarylcarboxylates including 2-aroylarylcarboxylates were realized by using [RuCl(benzene)(S)-SunPhos]Cl as the catalyst under mild reaction conditions. Excellent enantioselectivities (up to 99.6 % ee) and activities (S/C=1000) were obtained. This convenient and practical method enables a direct access to a series of highly optically pure 3-substituted phthalides that are very important molecules as valuable pharmacological compounds and diversified synthons for medicinal chemistry. Moreover, a gram-scale reaction was performed to further demonstrate the practicality of this approach.
- Lu, Bin,Zhao, Mengmeng,Ding, Guangni,Xie, Xiaomin,Jiang, Lili,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
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p. 3989 - 3996
(2017/09/13)
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- Preparation method of o-arylformacyl benzoate
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The invention provides a preparation method of o-arylformacyl benzoate.3-alkoxyisobenzofuryl ketone compounds used as the raw material are subjected to rearrangement reaction under the protonic acid catalytic condition to obtain the o-arylformacyl benzoate.
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Paragraph 0013-0014
(2017/07/19)
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- Iodobenzene-Catalyzed Synthesis of Phenanthridinones via Oxidative C-H Amidation
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We report a novel synthesis of phenanthridinones from N-methoxybenzamides using an oxidative C-H amidation reaction at room temperature in open air with modest to excellent yields. This method demonstrated unprecedented substrate scope. In particular, it solved the long-standing challenge in the synthesis of phenanthridinones with sterically demanding substitutions.
- Liang, Dongdong,Yu, Wenbo,Nguyen, Nam,Deschamps, Jeffrey R.,Imler, Gregory H.,Li, Yue,MacKerell, Alexander D.,Jiang, Chao,Xue, Fengtian
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p. 3589 - 3596
(2017/04/11)
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- Palladium-Catalyzed Environmentally Benign Acylation
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Recent trends in research have gained an orientation toward developing efficient strategies using innocuous reagents. The earlier reported transition-metal-catalyzed carbonylations involved either toxic carbon monoxide (CO) gas as carbonylating agent or functional-group-assisted ortho sp2 C-H activation (i.e., ortho acylation) or carbonylation by activation of the carbonyl group (i.e., via the formation of enamines). Contradicting these methods, here we describe an environmentally benign process, [Pd]-catalyzed direct carbonylation starting from simple and commercially available iodo arenes and aldehydes, for the synthesis of a wide variety of ketones. Moreover, this method comprises direct coupling of iodoarenes with aldehydes without activation of the carbonyl and also without directing group assistance. Significantly, the strategy was successfully applied to the synthesis n-butylphthalide and pitofenone.
- Suchand, Basuli,Satyanarayana, Gedu
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p. 6409 - 6423
(2016/08/16)
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- Phosphine-Free, Heterogeneous Palladium-Catalyzed Atom-Efficient Carbonylative Cross-Coupling of Triarylbismuths with Aryl Iodides: Synthesis of Biaryl Ketones
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A novel and highly efficient heterogeneous palladium-catalyzed carbonylative cross-coupling of aryl iodides with triarylbismuths has been developed that proceeds smoothly at atmospheric CO pressure and provides a general and powerful tool for the preparation of various valuable biaryl ketones with high atom economy, good to excellent yield, and recyclability of the catalyst. The reaction is the first example of Pd-catalyzed carbonylative cross-coupling for the construction of biaryl ketones using triarylbismuths as substrates.
- Hao, Wenyan,Liu, Haiyi,Yin, Lin,Cai, Mingzhong
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p. 4244 - 4251
(2016/06/09)
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- Acylative Suzuki coupling of amides: Acyl-nitrogen activation via synergy of independently modifiable activating groups
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A highly efficient palladium-catalyzed acylative cross-coupling of carboxylic amides with arylboronic acids has been achieved via synergistic activation of the Cacyl-N bond by independently modifiable activating groups. Coupling of amides features not only good functional group tolerance but also modifiable reactivities to overcome steric hindrance. This journal is
- Li, Xijing,Zou, Gang
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p. 5089 - 5092
(2015/03/30)
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- Expedient carbonylation of aryl halides in aqueous or neat condition
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An expedient and versatile, microwave-assisted procedure for the carbonylation of aryl halides with boronic acids, alcohols or amines in water or under neat conditions has been developed. The reaction is catalyzed by fluorous, oxime-based palladacycle 1 that shows an excellent recyclable property and low levels of Pd leaching. To demonstrate the usefulness of the protocol, we applied it to the preparation of compounds of pharmaceutical interest, including a precursor of the reverse transcriptase inhibitor, niacin, benzocaine and butamben.
- Ang, Wei Jie,Lo, Lee-Chiang,Lam, Yulin
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p. 8545 - 8558
(2014/12/11)
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- Copper-catalyzed methyl esterification reactions via C-C bond cleavage
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The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.
- Zhu, Yan,Yan, Hong,Lu, Linhua,Liu, Defu,Rong, Guangwei,Mao, Jincheng
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p. 9898 - 9905
(2013/10/22)
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- Successful application of indirect electrooxidation for the transformation of biaryl methanols to the corresponding biaryl ketones
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Various biaryl methanols were electrooxidized into the corresponding biaryl ketones in good yields and under very mild reaction conditions. Because of the relatively high oxidation potential, bulky structure, and somewhat poor solubility, biaryl methanols do not readily undergo direct electrooxidative transformations as a synthetic step toward the corresponding biaryl ketones. Herein, we report the successful indirect electrooxidation of secondary biaryl methanols featuring the use of a slight excess amount of KI (1.2 equivalents, relative to the substrate) in MeOH. Copyright
- Okimoto, Mitsuhiro,Yoshida, Takashi,Hoshi, Masayuki,Chiba, Tomohito,Maeo, Kei
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experimental part
p. 3134 - 3139
(2011/10/01)
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- Easy-to-execute carbonylative arylation of aryl halides using molybdenum hexacarbonyl: Efficient synthesis of unsymmetrical diaryl ketones
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A versatile procedure for the synthesis of unsymmetrical diaryl ketones through a palladium-catalyzed carbonylative arylation of iodoarenes through easy-to-handle molybdenum hexacarbonyl as a condensed source of carbon monoxide is described. This method provides an efficient route to a wide variety of substituted diaryl ketones without direct use of high-pressure carbon monoxide. Copyright
- Jafarpour, Farnaz,Rashidi-Ranjbar, Parviz.,Kashani, Asieh Otaredi
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experimental part
p. 2128 - 2132
(2011/05/09)
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- A direct and mild conversion of tertiary aryl amides to methyl esters using trimethyloxonium tetrafluoroborate: A very useful complement to directed metalation reactions
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The scope and generality of a direct process for the conversion of tertiary amides directly to methyl esters has been investigated. The process involves a two-step, one pot procedure in which a tertiary amide is first treated with trimethyloxonium tetrafluoroborate to generate an imidate intermediate which is then hydrolyzed, generally by the addition of saturated aqueous sodium bicarbonate solution. Although this process fails for aliphatic amides, very good yields are realized for a variety of amides derived from aromatic carboxylic acids. Steric hindrance at the N-alkyl group is well tolerated; thus N,N-dimethyl, -diethyl, and -diisopropyl amides can all be utilized successfully. (C) 2000 Elsevier Science Ltd.
- Keck, Gary E,McLaws, Mark D,Wager, Travis T
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p. 9875 - 9883
(2007/10/03)
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- Isoindol-1-one analogues of 4-(2'-methoxyphenyl)-1-[2'-[N-(2'-pyridyl)- p-iodobenzamido]ethyl]piperazine (p-MPPI) as 5-HT1(A) receptor ligands
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In developing radioiodinated antagonists for in vivo imaging of 5- HT(1A) receptors with SPECT, a series of new arylpiperazine benzamido derivatives, including 4-(2'-methoxyphenyl)-l-[2'-[N-(2-pyridyl)-p- iodobenzamido]ethyl]piperazine (p-MPPI, 31) (K(d) = 0.36 nM), as potential ligands for 5-HT1(A) receptors were reported previously. However, rapid in vivo metabolism may have caused the breakdown of the amide bond of [123I]- 31 and rendered this agent obsolete as an in vivo imaging agent in humans. To improve the in vivo stability of 31, a series of cyclized amide analogues were designed and synthesized. In vitro binding, metabolic stability, and in vivo biodistribution of these new derivatives were investigated. Several five-membered-ring isoindol-1-ones displayed very high in vitro binding affinity, especially 2-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl}-6- nitro-3-phenyl-2,3-dihydroisoindol-1-one, 15, 3-hydroxy-6-iodo-2-{2-[4-(2- methoxyphenyl)piperazin-1-yl]ethyl}-3-phenyl-2,3-dihydroisoindol-1-one, 18, and 6-iodo-2-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl)}-3-phenyl-2,3- dihydroisoindol-1-one, 21, which showed K(i) values of 0.05, 0.65, and 0.07 nM, respectively. The affinities for 5-HT1(A) receptors of other cyclized amide derivatives, 5-(4-bromophenyl)-1-{2-[4-(2-methoxyphenyl)piperazin-1- yl]ethyl}pyrrolidin-2-one, 25, 5-(4-iodophenyl)-1,{2-[4-(2- methoxyphenyl)piperazin-1-yl]ethyl}pyrrolidin-2-one, 27, and 2-{2-[4-(2- methoxyphenyl)piperazin-1-yl]ethyl}-2,3-dihydroisoindol-1-one, 29, were 1.09, 2.54, and 14.9 nM, respectively. Compared to [125I]-31, iodinated cyclized amide derivatives [125I]-21 and [125I]-27 displayed a slower metabolism in human liver microsomal and cytosolic preparations. Biodistribution of [125I]-21 and [125I]-27 in rats (after an iv injection) displayed moderate to low brain uptakes with little or no specific localization in hippocampal region, where 5-HT1(A) receptors are concentrated. These data indicate that the new iodinated ligands showed high binding affinities and better metabolic stability but displayed unexpectedly low selective binding to 5-HT1(A) receptors in vivo. Additional structural modifications may be needed to correct the unfavorable properties displayed for these iodinated cyclized amide derivatives for in vivo biodistribution in rats.
- Zhuang, Zhi-Ping,Kung, Mei-Ping,Mu, Mu,Kung, Hank F.
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p. 157 - 166
(2007/10/03)
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- Synthesis of Aromatic Carbonyl Compounds via Thallation-Carbonylation of Arenes
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Simple arenes, substituted benzylic and β-phenylethyl alcohols, benzoic acid, phenylacetic acid, benzamide, acetanilide, phenylurea, and benzophenone have been thallated under variety of reaction conditions with thallium(III) trifluoroacetate and subsequently carbonylated with 19percent PdCl2, 2 equiv of LiCl, and MgO in either methanol or tetrahydrofuran under 1 atm of carbon monoxide to give aromatic esters, substituted phthalides and 3,4-dihydroisocoumarins, phthalic and homophthalic anhydride, phthalimide, and the ortho-substituted methyl esters of acetanilide, phenylurea, and benzophenone, respectively.The scope and limitations of this approach to aromatic carbonyl compounds are examined.
- Larock, Richard C.,Fellows, Constance A.
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p. 1900 - 1907
(2007/10/02)
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- Deactivation of Triplet Phenyl Alkyl Ketones by Conjugatively Electron-Withdrawing Substituents
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Para-cyano, -carbomethoxy, and -acyl substituents decrease the triplet reactivity of valerophenone (γ-hydrogen abstraction), whereas comparable meta substituents increase reactivity.Spectroscopic results are presented which indicate that para-(-R) substituents lower ?,?* triplet energies so much more than n,?* energies that the lowest triplets become largely ?,?* in nature.Meta-(-R) substituents do not stabilize ?,?* triplets enough to invert triplet levels.Both substitution patterns support a largely 1,4-biradical structure for the lowest ?,?* triplet of acylbenzenes.Ortho substituents show the usual steric anomalies: ortho cyano enhances valerophenone triplet reactivity by stabilizing the n,?* triplet; ortho carbomethoxy deactivates valerophenone by stabilizing the ?,?* triplet but not the n,?.*
- Wagner, Peter J.,Siebert, Elizabeth J.
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p. 7329 - 7335
(2007/10/02)
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