- Synthesis of α-Keto Acids via Oxidation of Alkenes Catalyzed by a Bifunctional Iron Nanocomposite
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An efficient methodology for synthesis of α-keto acids via oxidation of alkenes using TBHP as oxidant catalyzed by a bifunctional iron nanocomposite has been established. A variety of alkenes with different functional groups were smoothly oxidized into their corresponding α-keto acids in up to 80% yield. Moreover, the bifunctional iron nanocomposite catalyst showed outstanding catalytic stability for successive recycles without appreciable loss of activity.
- Song, Tao,Ma, Zhiming,Wang, Xiaoxue,Yang, Yong
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supporting information
p. 5917 - 5921
(2021/07/31)
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- Silyl Cyanopalladate-Catalyzed Friedel-Crafts-Type Cyclization Affording 3-Aryloxindole Derivatives
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3-Aryloxindole derivatives were synthesized through a Friedel-Crafts-type cyclization. The reaction was catalyzed by a trimethylsilyl tricyanopalladate complex generated in situ from trimethylsilyl cyanide and Pd(OAc) 2. Wide varieties of diethyl phosphates derived from N -arylmandelamides were converted almost quantitatively into oxindoles. When N, N -dibenzylamide was used instead of an anilide substrate, a benzo-fused δ-lactam was obtained. An oxindole product was subjected to substitution reactions to afford 3,3-diaryloxindoles with two different aryl groups.
- Ece, Hamdiye,Tange, Yuji,Yurino, Taiga,Ohkuma, Takeshi
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p. 935 - 939
(2021/02/22)
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- Photoinduced homolytic decarboxylative acylation/cyclization of unactivated alkenes with α-keto acid under external oxidant and photocatalyst free conditions: access to quinazolinone derivatives
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A novel and green strategy for the synthesis of acylated quinazolinone derivativesviaphoto-induced decarboxylative cascade radical acylation/cyclization of quinazolinone bearing unactivated alkenes has been developed. The protocol provides a novel route to access acyl radicals from α-keto acids through a self-catalyzed energy transfer process. Most importantly, the reaction proceeded smoothly without any external photocatalyst, additive or oxidant, and could be easily scaled-up in flow conditions with sunlight irradiation.
- Sun, Bin,Shi, Rongcheng,Zhang, Kesheng,Tang, Xiaoli,Shi, Xiayue,Xu, Jiayun,Yang, Jin,Jin, Can
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supporting information
p. 6050 - 6053
(2021/06/21)
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- Hypervalent Iodine(III)-Promoted Radical Oxidative C-H Annulation of Arylamines with α-Keto Acids
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A novel catalyst-free radical oxidative C-H annulation reaction of arylamines with α-keto acids toward benzoxazin-2-ones synthesis under mild conditions was developed. This hypervalent iodine(III)-promoted process eliminated the use of a metal catalyst or additive with high levels of functional group tolerance. Hypervalent iodine(III) was both an oxidant and a radical initiator for this reaction. The synthetic utility of this method was confirmed by the synthesis of the natural product cephalandole A.
- Long, Lipeng,Wang, Jieyan,Gu, Liuqing,Yang, Shiguang,Qiao, Liang,Luo, Guotian,Chen, Zhengwang
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supporting information
p. 12084 - 12092
(2021/08/24)
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- Visible-Light-Promoted Switchable Synthesis of C-3-Functionalized Quinoxalin-2(1H)-ones
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A visible-light-promoted synthesis of quinoxalin-2(1H)-ones has been developed using 9-mesityl-10-methylacridinium perchlorate as an organo-photocatalyst. The atmosphere-controlled method (Ar/air) enabled the selective synthesis of hydroxyl- and acyl-containing quinoxalin-2(1H)-ones under mild reaction conditions without the use of any metal catalysts or toxic reagents. A fluorescent labelling experiment showed that hydroxyl-containing quinoxalin-2(1H)-ones may have utility in various biological applications as potent fluorophores. (Figure presented.).
- Aganda, Kim Christopher C.,Hong, Boseok,Lee, Anna
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supporting information
p. 1443 - 1448
(2021/01/26)
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- Direct 1,2-Dicarbonylation of Alkenes towards 1,4-Diketones via Photocatalysis
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1,4-Dicarbonyl compounds are intriguing motifs and versatile precursors in numerous pharmaceutical molecules and bioactive natural compounds. Direct incorporation of two carbonyl groups into a double bond at both ends is straightforward, but also challenging. Represented herein is the first example of 1,2-dicarbonylation of alkenes by photocatalysis. Key to success is that N(n-Bu)4+ not only associates with the alkyl anion to avoid protonation, but also activates the α-keto acid to undergo electrophilic addition. The α-keto acid is employed both for acyl generation and electrophilic addition. By tuning the reductive and electrophilic ability of the acyl precursor, unsymmetric 1,4-dicarbonylation is achieved for the first time. This metal-free, redox-neutral and regioselective 1,2-dicarbonylation of alkenes is executed by a photocatalyst for versatile substrates under extremely mild conditions and shows great potential in biomolecular and drug molecular derivatization.
- Chen, Bin,Cheng, Yuan-Yuan,Hou, Hong-Yu,Lei, Tao,Tung, Chen-Ho,Wu, Li-Zhu,Yu, Ji-Xin
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supporting information
p. 26822 - 26828
(2021/11/17)
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- Diazotrifluoroethyl Radical: A CF3-Containing Building Block in [3 + 2] Cycloaddition
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We present herein a visible-light-induced [3 + 2] cycloaddition of a hypervalent iodine(III) reagent with α-ketoacids for the construction of 5-CF3-1,3,4-oxadiazoles that are of importance in medicinal chemistry. The reaction proceeds smoothly without a photocatalyst, metal, or additive under mild conditions. Different from the well-established trifluorodiazoethane (CF3CHN2), the diazotrifluoroethyl radical [CF3C(·)N2], a trifluoroethylcarbyne (CF3C?:) equivalent and an unusual CF3-containing building block, is involved in the present reaction system.
- Zhao, Wen-Wen,Shao, Yong-Chao,Wang, An-Ni,Huang, Jia-Li,He, Chun-Yang,Cui, Bao-Dong,Wan, Nan-Wei,Chen, Yong-Zheng,Han, Wen-Yong
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supporting information
p. 9256 - 9261
(2021/12/06)
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- Arylglyoxylic acid as well as preparation method and application thereof
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The invention relates to arylglyoxylic acid as well as a preparation method and application thereof, and the method comprises the following steps: carrying out hydrolysis reaction on arylglyoxylonitrile oxime as shown in a formula (I) under the catalysis of an inorganic acid to obtain arylglyoxylic acid as shown in a formula (II). The arylglyoxylic acid prepared by the preparation method is high in yield, high in product purity, simple to operate, environment-friendly and pollution-free. The arylglyoxylic acid is used as a fine chemical synthesis intermediate.
- -
-
Paragraph 0053-0057
(2021/01/15)
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- Metal-free C3-H acylation of quinoxalin-2(1: H)-ones with α-oxo-carboxylic acids
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Direct C3-H acylation of quinoxalin-2(1H)-ones with α-oxocarboxylic acids under thermo conditions promoted by PIDA has been achieved in a moderate to good yield in a very fast manner. Mechanistic study revealed that the reaction proceeds via a radical pro
- Li, Yu,Ni, Hangcheng,Shi, Xingzi,Zhang, Xiaoning,Zhao, Fei,Zhao, Jingwei
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supporting information
p. 6558 - 6563
(2020/09/04)
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- Photoredox Catalysis Enables Decarboxylative Cyclization with Hypervalent Iodine(III) Reagents: Access to 2,5-Disubstituted 1,3,4-Oxadiazoles
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A novel approach to 2,5-disubstituted 1,3,4-oxadiazoles derivatives via a decarboxylative cyclization reaction by photoredox catalysis between commercially available α-oxocarboxylic acids and hypervalent iodine(III) reagent is described. This powerful transformation involves the coupling reaction between two different kinds of radical species and the formation of C-N and C-O bonds.
- Li, Jian,Lu, Xue-Chen,Xu, Yue,Wen, Jin-Xia,Hou, Guo-Quan,Liu, Li
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supporting information
p. 9621 - 9626
(2020/12/21)
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- Visible-Light-Induced Decarboxylative Cyclization/Hydrogenation Cascade Reaction to Access Phenanthridin-6-yl(aryl)methanol by an Electron Donor-Acceptor Complex
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A novel and efficient visible-light-induced decarboxylative cyclization/hydrogenation cascade reaction of α-oxocarboxylic acids and 2-isocyanobiaryls has been developed. Without the need of any external photosensitizer, oxidant, and reductant, this method offers a mild and green approach for the synthesis of diverse alcohols in moderate to good yields. A mechanism indicated that an electron donor-acceptor complex-driven decarboxylation, radical addition/cyclization, and in situ photochemical reduction of ketones to alcohols could be involved in the reaction.
- Shi, Wei,Ma, Fang,Li, Pinhua,Wang, Lei,Miao, Tao
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p. 13808 - 13817
(2020/11/20)
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- General Synthesis of Chiral α,α-Diaryl Carboxamides by Enantioselective Palladium-Catalyzed Cross-Coupling
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A general synthesis of chiral α,α-diaryl carboxamides is developed by enantioselective cross-coupling between 2-bromo-2-aryl carboxamides and arylboronic acids, leading to a series of chiral α,α-diaryl carboxamides with various electronic properties and functionalities in moderate to excellent enantioselectivities and yields. The employment of a sterically bulky chiral P,P═O ligand L2 is critical for the reactivity and selectivity. This protocol is applied to an efficient asymmetric synthesis of a key intermediate of dopamine receptor agonist SKF 38393.
- Li, Bowen,Aliyu, Muinat A.,Gao, Zhenhua,Li, Tiejun,Dong, Wei,Li, Junchen,Shi, Enxue,Tang, Wenjun
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supporting information
p. 4974 - 4978
(2020/07/03)
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- Electrochemical synthesis of enaminones: Via a decarboxylative coupling reaction
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An environmentally benign and efficient electrochemical synthesis of enaminones via a decarboxylative coupling reaction of α-keto acids using n-Bu4NI as a redox catalyst and electrolyte under constant current electrolysis in an undivided cell is reported. A broad vinyl azide substrate scope and high functional group tolerance are observed. A gram-scale reaction further demonstrates the practicability of the protocol. The results of cyclic voltammetry and control experiments indicate that I2 is likely the active species to initiate the oxidative decarboxylation via an acyl hypoiodite intermediate.
- Kong, Xianqiang,Liu, Yulong,Lin, Long,Chen, Qianjin,Xu, Bo
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supporting information
p. 3796 - 3801
(2019/07/31)
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- Pd(OAc)2-Catalyzed Asymmetric Hydrogenation of α-Iminoesters
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An efficient Pd(OAc)2-catalyzed asymmetric hydrogenation of α-iminoesters was realized for the first time at 1 atm hydrogen pressure and room temperature. Pd(OAc)2, a less expensive Pd salt with low toxicity, was found to be the most suitable catalyst precursor rather than Pd(TFA)2 which is usually the catalyst of choice for homogeneous asymmetric hydrogenation. The chiral α-arylglycine fragments are widely found in many chiral products and bioactive molecules.
- Chen, Jianzhong,Li, Feilong,Wang, Fang,Hu, Yawen,Zhang, Zhenfeng,Zhao, Min,Zhang, Wanbin
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supporting information
p. 9060 - 9065
(2019/11/19)
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- Direct Acyl Radical Addition to 2 H-Indazoles Using Ag-Catalyzed Decarboxylative Cross-Coupling of α-Keto Acids
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A direct acyl radical addition to 2H-indazoles has been achieved for the first time, where the less-aromatic quinonoid 2H-indazoles readily accepted radical species to the C-3 position. Motivated by the lack of direct acylation strategy for 2H-indazoles, the current method utilizes the radical acceptability of 2H-indazoles, discovering an ambient temperature reaction to provide facile access to a diverse array of 3-acyl-2H-indazoles with three points of structural diversification in 25%-83% yields.
- Bogonda, Ganganna,Kim, Hun Young,Oh, Kyungsoo
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supporting information
p. 2711 - 2715
(2018/05/22)
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- Visible-Light-Induced Decarboxylation Coupling/Intramolecular Cyclization: A One-Pot Synthesis for 4-Aryl-2-quinolinone Derivatives
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A visible-light-induced decarboxylation coupling/intramolecular cyclization is reported. The one-pot synthesis system provides mild, efficient, and atom economical access to the synthesis of 4-aryl-2-quinolinone derivatives. It is notable that the necessa
- Wang, Chenglong,Qiao, Jingyi,Liu, Xiaochong,Song, He,Sun, Zhizhong,Chu, Wenyi
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p. 1422 - 1430
(2018/02/09)
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- Anti-Selective Catalytic Asymmetric Nitroaldol Reaction of α-Keto Esters: Intriguing Solvent Effect, Flow Reaction, and Synthesis of Active Pharmaceutical Ingredients
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A rare-earth metal/alkali metal bimetallic catalyst proved particularly effective for enantioselectively coupling nitroalkanes and α-keto esters in an anti-selective manner to afford synthetically versatile, densely functionalized, and optically active α-nitro tertiary alcohols. A chiral diamide ligand captured two distinct metal cations, giving rise to a catalytically competent solid-phase heterobimetallic catalyst by simple mixing via self-assembly. The advantage of the solid-phase asymmetric catalyst was realized by successful application to the enantio- and diastereoselective reaction in a continuous-flow platform. The use of closely related solvents in terms of structures and polarity parameters, THF and its methylated congener 2-Me-THF, had an unexpectedly large solvent effect both on the reaction rate and the stereoselectivity. The nitroaldol products share a privileged unit for active pharmaceutical ingredients, as demonstrated by the streamlined enantioselective synthesis of the marketed antifungal agents efinaconazole and albaconazole.
- Karasawa, Tomoya,Oriez, Rapha?l,Kumagai, Naoya,Shibasaki, Masakatsu
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supporting information
p. 12290 - 12295
(2018/09/27)
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- Domino Synthesis of α,β-Unsaturated γ-Lactams by Stereoselective Amination of α-Tertiary Allylic Alcohols
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Tertiary allylic alcohols equipped with a carboxyl group can be smoothly aminated under ambient conditions by a conceptually new and stereoselective protocol under palladium catalysis. The in situ formed Z-configured γ-amino acid cyclizes to afford an α,β-unsaturated γ-lactam, releasing water as the only byproduct. This practical catalytic transformation highlights the use of a carboxyl group acting as an activating and stereodirecting functional group to provide a wide series of pharma-relevant building blocks. Various control reactions support the crucial role of the carboxyl group in the substrate to mediate these transformations.
- Xie, Jianing,Xue, Sijing,Escudero-Adán, Eduardo C.,Kleij, Arjan W.
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supporting information
p. 16727 - 16731
(2018/11/23)
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- Reductive carboxylation of aromatic esters by electron transfer from magnesium metal
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Magnesium-promoted reductive carboxylation of ethyl benzoate in the presence of chlorotrimethylsilane in N,N-dimethylformamide brought about a new carbon-carbon bond formation between the carbonyl carbon atom and carbon dioxide to give the corresponding benzoylformic acid in good yield. It is noteworthy that only ethyl benzoates with substituents at the meta-position were converted into benzoylformic acid derivatives. Moreover, no mandelic acid was detected even under the reductive conditions. This result indicates that benzoylformic acid was obtained after hydrolysis of a carboxylated intermediate, which would be alive as a stabilized structure in the reaction media.
- Maekawa, Hirofumi,Okawara, Hikaru,Murakami, Taro
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supporting information
p. 206 - 209
(2016/12/28)
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- The Synthesis of Chiral α-Aryl α-Hydroxy Carboxylic Acids via RuPHOX-Ru Catalyzed Asymmetric Hydrogenation
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A ruthenocenyl phosphino-oxazoline-ruthenium complex (RuPHOX?Ru) catalyzed asymmetric hydrogenation of α-aryl keto acids has been successfully developed, affording the corresponding chiral α-aryl α-hydroxy carboxylic acids in high yields and with up to 97% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 5000 S/C) and the resulting products can be transformed to several chiral building blocks, biologically active compounds and chiral drugs. (Figure presented.).
- Guo, Huan,Li, Jing,Liu, Delong,Zhang, Wanbin
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supporting information
p. 3665 - 3673
(2017/09/11)
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- Aldehydes as Carbon Radical Acceptors: Silver Nitrate Catalyzed Cascade Decarboxylation and Oxidative Cyclization toward Dihydroflavonoid Derivatives
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Silver nitrate-catalyzed cascade decarboxylation and oxidative cyclization of α-oxocarboxylic acids, alkenes, and aldehydes is demonstrated for the first time. With ammonium persulfate as the oxidant, the cascade reactions afford dihydroflavonoid derivatives as products in moderate to good yields, exhibiting a broad substrate tolerance. Control experiments indicated that the mechanism includes a radical pathway with aldehydes as the carbon radical acceptors. (Figure presented.).
- Yang, Wen-Chao,Dai, Peng,Luo, Kai,Ji, Yi-Gang,Wu, Lei
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supporting information
p. 2390 - 2395
(2017/07/22)
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- Palladium-catalyzed decarboxylative, decarbonylative and dehydrogenative C(sp2)-H acylation at room temperature
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Over the past few decades, an impressive array of C-H activation methodology has been developed for organic synthesis. However, due to the inherent inertness of the C-H bonds (e.g. ~110 kcal mol-1 for the cleavage of C(aryl)-H bonds) harsh reaction conditions have been realized to overcome high energetic transition states resulting in a limited substrate scope and functional group tolerance. Therefore, the development of mild C-H functionalization protocols is in high demand to exploit the full potential of the C-H activation strategy in the synthesis of a complex molecular framework. Although, electron-rich substrates undergo electrophilic metalation under relatively mild conditions, electron-deficient substrates proceed through a rate-limiting C-H insertion under forcing conditions at high temperature. In addition, a stoichiometric amount of toxic silver salt is frequently used in palladium catalysis to facilitate the C-H activation process which is not acceptable from the environmental and industrial standpoint. We report herein, a Pd(ii)-catalyzed decarboxylative C-H acylation of 2-arylpyridines with α-ketocarboxylic acids under mild conditions. The present protocol does not require stoichiometric silver(i) salts as additives and proceeds smoothly at ambient temperature. A novel decarbonylative C-H acylation reaction has also been accomplished using aryl glyoxals as acyl surrogates. Finally, a practical C-H acylation via a dehydrogenative pathway has been demonstrated using commercially available benzaldehydes and aqueous hydroperoxides. We also disclose that acetonitrile solvent is optimal for the acylation reaction at room temperature and has a prominent role in the reaction outcome. Control experiments suggest that the acylation reaction via decarboxylative, decarbonylative and dehydrogenative proceeds through a radical pathway. Thus we disclose a practical protocol for the sp2 C-H acylation reaction.
- Hossian, Asik,Manna, Manash Kumar,Manna, Kartic,Jana, Ranjan
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supporting information
p. 6592 - 6603
(2017/08/16)
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- N-Heterocyclic Carbene-Catalyzed Umpolung of Alkynyl 1,2-Diketones
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The umpolung of alkynyl 1,2-diketones via N-heterocyclic carbene (NHC) catalysis was achieved for the first time, allowing the rapid access to a large variety of synthetically and pharmaceutically important α-pyrones under very mild conditions. A completely new NHC-catalyzed umpolung pattern involving an O-acylated allenolate as the key intermediate was proposed. Moreover, an unprecedented reaction pathway, featured by a series of group migrations and new bond formation, was postulated to demonstrate the formation of the products. (Figure presented.).
- Kong, Xiangwen,Zhang, Guoxiang,Yang, Shuang,Liu, Xiaozhi,Fang, Xinqiang
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supporting information
p. 2729 - 2734
(2017/08/23)
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- A Copper(I)-Catalyzed Addition/Annulation Sequence for the Two-Component Synthesis of γ-Ylidenebutenolides
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A highly efficient Cu(I)-catalyzed addition/annulation sequence has been developed for the synthesis of (Z)-ylidenebutenolides employing readily available α-ketoacids and alkynes as substrates. The reactions employ a simple commercially available Cu(I)-catalyst, display good substrate scope, and deliver products with high stereoselectivity. The synthetic utility of the method is demonstrated by the straightforward derivatization of the ylidenebutenolides into a diverse range of heterocycles, and also by the preparation of the natural product bovolide, and analogs thereof.
- Seo, Sangwon,Willis, Michael C.
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supporting information
p. 4556 - 4559
(2017/09/11)
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- Palladium-catalyzed ortho-acylation of N-Nitrosoanilines with α-oxocarboxylic acids: A convenient method to synthesize N-Nitroso ketones and indazoles
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An efficient and mild protocol for regioselective synthesis of N-Nitroso aryl ketones by palladium-catalyzed direct acylation of arenes using N-Nitroso as directing groups is described. This reaction proceeded smoothly and could tolerate a variety of functional groups. Moreover, this chemistry offers a convenient access to a range of indazoles.
- Zhang, Liang,Wang, Zhe,Guo, Peiyu,Sun, Wei,Li, Ya-Min,Sun, Meng,Hua, Chengwen
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supporting information
p. 2511 - 2514
(2016/05/24)
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- Silver-promoted decarboxylative amidation of α-keto acids with amines
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A general and effective method for the synthesis of amides through decarboxylative amidation of α-keto acids with amines has been developed. The reaction proceeded smoothly to afford the corresponding amide products in good yield under air and shows excellent functional group tolerance. In addition, the protocol can be further applied in the synthesis of heterocyclic compounds like benzimidazoles.
- Xu, Xiao-Lan,Xu, Wen-Tao,Wu, Ji-Wei,He, Jian-Bo,Xu, Hua-Jian
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supporting information
p. 9970 - 9973
(2016/11/06)
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- Copper-catalyzed direct α-ketoesterification of propiophenones with acetophenones via C(sp3)-H oxidative cross-coupling
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A novel copper-catalyzed direct α-ketoesterification of propiophenones with acetophenones via C(sp3)-H oxidative cross-coupling was developed. The reaction utilized O2 as a clean oxidant with high atom economy and the starting materials are facile and commercially available.
- Du, Juan,Zhang, Xiuli,Sun, Xi,Wang, Lei
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supporting information
p. 4372 - 4375
(2015/03/30)
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- Organocatalytic Enantioselective Michael Reaction of Malononitrile with β,β-Disubstituted Nitroalkenes
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We have developed and optimized an enantioselective Michael reaction of malononitrile with β,β-disubstituted nitroalkenes. This reaction was catalyzed by a cinchona alkaloid derived thiourea catalyst, producing products of high yields (up to 98 %) and ste
- Chen, Shengwei,Lou, Qinxin,Ding, Yuyang,Zhang, Shasha,Hu, Wenhui,Zhao, Junling
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supporting information
p. 2437 - 2441
(2015/08/18)
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- Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
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A new efficient and highly enantioselective direct asymmetric hydrogenation of α-keto acids employing the Ir/SpiroPAP catalyst under mild reaction conditions has been developed. This method might be feasible for the preparation of a series of chiral α-hydroxy acids on a large scale.
- Yan, Pu-Cha,Xie, Jian-Hua,Zhang, Xiang-Dong,Chen, Kang,Li, Yuan-Qiang,Zhou, Qi-Lin,Che, Da-Qing
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supporting information
p. 15987 - 15990
(2015/02/19)
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- Nickel-catalyzed decarboxylative acylation of heteroarenes by sp 2 C-H functionalization
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Nickel-catalyzed ligand-free decarboxylative cross-coupling of azole derivatives with α-oxoglyoxylic acids has been developed. This work represents the first example of decarboxylative cross-coupling reactions, in a C-H bond functionalization manner, thro
- Yang, Ke,Zhang, Cheng,Wang, Peng,Zhang, Yan,Ge, Haibo
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supporting information
p. 7241 - 7244
(2014/06/23)
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- Asymmetric friedel-crafts alkylation of α-substituted β-nitroacrylates: Access to β2,2-amino acids bearing indolic all-carbon quaternary stereocenters
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A highly enantioselective Friedel-Crafts alkylation reaction of indoles with acyclic α-substituted β-nitroacrylates is developed under the catalysis of Ni(ClO4)2-bisoxazoline complex at 1 mol % catalyst loading, affording chiral indolic β-nitroesters bearing all-carbon quaternary stereocenters in excellent yields and ees of up to 97%. Transformation of one of the products to β2,2-amino ester and tetrahydro-β-carboline through nitro reduction and sequential Pictet-Spengler cyclization was exemplified.
- Weng, Jian-Quan,Deng, Qiao-Man,Wu, Liang,Xu, Kai,Wu, Hao,Liu, Ren-Rong,Gao, Jian-Rong,Jia, Yi-Xia
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supporting information
p. 776 - 779
(2014/03/21)
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- Cationic Ir/Me-BIPAM-catalyzed asymmetric intramolecular direct hydroarylation of α-ketoamides
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Asymmetric intramolecular direct hydroarylation of α-ketoamides gives various types of optically active 3-substituted 3-hydroxy-2-oxindoles in high yields with complete regioselectivity and high enantioselectivities (84-98 % ee). This is realized by the use of the cationic iridium complex [Ir(cod) 2](BArF4) and the chiral O-linked bidentate phosphoramidite (R,R)-Me-BIPAM. Carbon's got a brand new bond: Asymmetric intramolecular direct hydroarylation of α-ketoamides gives various optically active 3-substituted 3-hydroxy-2-oxindoles in high yields with complete regioselectivity and high enantioselectivities. This is realized by the use of an asymmetric cationic iridium complex formed in situ (see Scheme).
- Shirai, Tomohiko,Ito, Hajime,Yamamoto, Yasunori
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supporting information
p. 2658 - 2661
(2014/03/21)
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- Enantio- and chemoselective Br?nsted-acid/Mg(nBu) 2 catalysed reduction of α-keto esters with catecholborane
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The first enantio- and chemoselective Br?nsted-acid catalysed reduction of α-keto esters with catecholborane has been developed. The α-hydroxy esters were obtained under mild reaction conditions in virtually quantitative yields and excellent enantioselectivities. With slight modifications both enantiomers can be obtained without any loss of selectivity. This journal is the Partner Organisations 2014.
- Enders, Dieter,St?ckel, Bianca A.,Rembiak, Andreas
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supporting information
p. 4489 - 4491
(2014/04/17)
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- Rh(I)-catalyzed intermolecular hydroacylation: Enantioselective cross-coupling of aldehydes and ketoamides
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Under Rh(I) catalysis, α-ketoamides undergo intermolecular hydroacylation with aliphatic aldehydes. A newly designed Josiphos ligand enables access to α-acyloxyamides with high atom-economy and enantioselectivity. On the basis of mechanistic and kinetic s
- Kou, Kevin G. M.,Le, Diane N.,Dong, Vy M.
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supporting information
p. 9471 - 9476
(2014/07/21)
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- Palladium-catalyzed decarboxylative acylation of O-methyl ketoximes with α-keto acids
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A mild, practical and efficient palladium-catalyzed decarboxylative ortho-acylation of O-methyl ketoximes with α-keto acids via C-H bond activation is described. In these reactions, a broad range of O-methyl ketoximes and α-keto acids undergoes the decarboxylative cross-coupling reactions with high selectivities and good tolerance. The Royal Society of Chemistry 2013.
- Kim, Minyoung,Park, Jihye,Sharma, Satyasheel,Kim, Aejin,Park, Eonjeong,Kwak, Jong Hwan,Jung, Young Hoon,Kim, In Su
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supporting information
p. 925 - 927
(2013/02/23)
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- Pd(ii)-catalyzed decarboxylative acylation of phenylacetamides with α-oxocarboxylic acids via C-H bond activation
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A palladium-catalyzed decarboxylative acylation of phenylacetamides with α-oxocarboxylic acids via C-H bond activation is described. This protocol provides efficient access to a range of ortho-acyl phenylacetamides, which can be easily converted to 3-isochromanone derivatives. The Royal Society of Chemistry 2013.
- Park, Jihye,Kim, Minyoung,Sharma, Satyasheel,Park, Eonjeong,Kim, Aejin,Lee, Sang Hwi,Kwak, Jong Hwan,Jung, Young Hoon,Kim, In Su
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supporting information
p. 1654 - 1656
(2013/03/14)
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- Palladium-catalyzed decarboxylative acylation of O-phenyl carbamates with α-oxocarboxylic acids at room temperature
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A palladium-catalyzed oxidative acylation of O-phenyl carbamates with α-oxocarboxylic acids via selective aromatic C-H bond activation is described. This protocol represents the first ortho-acylation of phenol derivatives, and a catalytic amount of triflic acid additive is crucial for this transformation. Copyright
- Sharma, Satyasheel,Kim, Aejin,Park, Eonjeong,Park, Jihye,Kim, Minyoung,Kwak, Jong Hwan,Lee, Sang Hwi,Jung, Young Hoon,Kim, In Su
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supporting information
p. 667 - 672
(2013/04/11)
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- NOVEL ADENINE COMPOUND AND USE THEREOF
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A drug for topically administration which is effective as an antiallergic agent. The drug for topically administration contains as an active ingredient an adenine compound represented by the general formula (1): [wherein ring A represents a 6 to 10 membered, mono or bicyclic, aromatic hydrocarbon or a 5 to 10 membered, mono or bicyclic, aromatic heterocycle containing one to three heteroatoms selected among 0 to 2 nitrogen atoms, 0 or 1 oxygen atom, and 0 or 1 sulfur atom; n is an integer of 0 to 2; m is an integer of 0 to 2; R represents halogeno, (un)substituted alkyl, etc.; X1 represents oxygen, sulfur, NR1 (R1 represents hydrogen or alkyl), or a single bond; Y1 represents a single bond, alkylene; etc.; Y2 represents a single bond, alkylene, etc.; Z represents alkylene; and at least one of Q1 and Q2 represents -COOR10 (wherein R10 represents (un)substituted alkyl, etc.), etc.] or a pharmaceutically acceptable salt of the compound.
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Page/Page column 29
(2010/02/12)
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- Reduction of manganate(VI) by mandelic acid and its significance to development of a general mechanism for oxidation of organic compounds by high-valent transition metal oxides
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Results obtained from a study of the oxidation of mandelic acid and cyclobutanol by manganate(VI) indicate that reaction mechanisms traditionally applied to oxidations of this type (i.e., hydrogen atom or hydride ion transfers) may not be correct. Instead it appears that the reaction may be initiated by a 2 + 2 addition of the α-C-H bond to a manganese oxo double bond. This interpretation may be useful in the development of a general mechanism for the oxidation of organic compounds by high-valent transition metal oxides including more common oxidants such as permanganate, ruthenium tetroxide, and chromic acid.
- Lee, Donald G.,Chen, Tao
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p. 11231 - 11236
(2007/10/02)
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- The Oxidation of Alcohols by Permanganate. A Comparison with Other High-Valent Transition-Metal Oxidants
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The results obtained from a study of the oxidation of mandelic acid and cyclobutanol by permanganate in 1.0 M KOH are best accomodated by a mechanism in which the initial reaction is the addition of a manganese-oxo bond to the α-C-H bond of the alcohol, followed by homolytic cleavage of the resulting Mn-C bond to give free-radical intermediates.A comparison with other high-valent transition-metal oxidants suggests that it is possible to systematically classify the way in which these reagents react with alcohols on the basis of the initial reaction (C-H or O-H addition) and the cleavage mode of the metal-oxygen or metal-carbon bond (homolytic or heterolytic).The approach provides a framework for understanding these reactions that is less chaotic than the current situation where distinctive mechanisms have been proposed for each individual oxidant.
- Lee, Donald G.,Chen, Tao
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p. 5341 - 5345
(2007/10/02)
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- COBALT-CATALYZED LOW PRESSURE DOUBLE CARBONYLATION OF ARYL AND SECONDARY BENZYL HALIDES
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α-Ketoacids can be easily synthesized with satisfactory yields and selectivities by carbonylation of aryl halides and secondary benzyl halides under very mild conditions.The reactions are catalyzed by Co2(CO)8 in alcoholic solvents; the presence of a methyl source (dimethyl sulfate or methyl iodide) is necessary for the carbonylation of the aryl halides.Base, temperature and solvent have large effects on the course of the reaction.
- Francalanci, F.,Bencini, E.,Gardano, A.,Vincenti, M.,Foa, M.
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p. C27 - C30
(2007/10/02)
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