- Tris(pentafluorophenyl)borane-Catalyzed Oxygen Insertion Reaction of α-Diazoesters (α-Diazoamides) with Dimethyl Sulfoxide
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A tris(pentafluorophenyl)borane-catalyzed oxidation reaction of α-diazoesters (α-diazo amides) with dimethyl sulfoxide has been developed. The reaction proceeds under metal free conditions to afford a series α-ketoesters and α-ketoamides. The synthetic utility of this protocol is demonstrated through synthetic transformations and scaled-up synthesis. (Figure presented.).
- Wu, Xiao-Yang,Gao, Wen-Xia,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 750 - 754
(2022/01/19)
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- Palladium-Catalyzed Asymmetric Hydroesterification of α-Aryl Acrylic Acids to Chiral Substituted Succinates
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A palladium-catalyzed asymmetric hydroesterification of α-aryl acrylic acids with CO and alcohol was developed, preparing a variety of chiral α-substituted succinates in moderate yields with high ee values. The kinetic profile of the reaction progress revealed that the alkene substrate first underwent the hydroesterification followed by esterification with alcohol. The origin of the enantioselectivity was elucidated by density functional theory computation.
- Ji, Xiaolei,Shen, Chaoren,Tian, Xinxin,Dong, Kaiwu
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supporting information
p. 8645 - 8649
(2021/10/25)
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- Preparation method of alpha-naphthylacetic acid
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The invention relates to the technical field of organic synthesis, and provides a preparation method of alpha-naphthylacetic acid. The invention aims to solve the problem that preparation of alpha-naphthylacetic acid is not economical and environmentally friendly in the prior art. The preparation method comprises the following steps: (1) dissolving naphthalene and Lewis acid in a solvent, carryingout heating, adding oxalyl chloride monoester, and carrying out a reaction to generate alpha-acetonaphthone acid ester; and (2) adding the alpha-acetonaphthone acid ester obtained in the step (1) andhydrazine hydrate into a high-boiling-point alcohol solvent, carrying out a heating reaction, adding a strong base, continuing the heating reaction, and adjusting a pH value to an acidic state afterthe reaction is finished so as to obtain alpha-naphthylacetic acid. According to the method, naphthalene and oxalyl chloride monoester which are cheap and easy to obtain are used as raw materials, alpha-acetonaphthone acid ester is prepared under the action of Lewis acid, and then a series of reactions are performed under the action of hydrazine hydrate to generate alpha-naphthylacetic acid, so the use of highly toxic cyanide is avoided, highly toxic or foul gas is not generated in the reaction process, only one product is produced, reaction conditions are mild, yield is high and cost is low.
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Paragraph 0009; 0021; 0025
(2020/08/22)
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- Ambient and aerobic carbon-carbon bond cleavage toward α-ketoester synthesis by transition-metal-free photocatalysis
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The α-oxoesterification of the CC double bond in readily available enaminones enabling efficient synthesis of α-ketoesters is developed. The reactions showing general tolerance to the reactions of primary and secondary alcohols proceed well under air via Rose Bengal (RB)-based photocatalysis. Particularly, this mild synthetic method has been discovered to tolerate various polyhydroxylated substrates such as phenolic alcohol, diols and triols with an excellent selectivity of mono-oxoesterification. What is more noteworthy is that α-ketoester functionalized 16-dehydropregnenolone acetate resulting from the elaboration on a natural product has been obtained practically.
- Yu, Qing,Zhang, Yating,Wan, Jie-Ping
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supporting information
p. 3436 - 3441
(2019/06/24)
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- Switchable C-H Functionalization of N-Tosyl Acrylamides with Acryloylsilanes
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A controllable Rh-catalyzed protocol to access alkylation and alkenylation-annulation of N-tosyl acrylamide with acryloyl silane is reported. In contrast to the directing group or catalyst-dependent divergent sp2 C-H alkylation/alkenylation, the intrinsic property of acryloylsilane allows the switchable reaction manifold, thereby affording either alkylation or annulation products with slight modification of the reaction conditions.
- Song, Shengjin,Lu, Ping,Liu, Huan,Cai, Sai-Hu,Feng, Chao,Loh, Teck-Peng
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supporting information
p. 2869 - 2872
(2017/06/13)
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- Asymmetric Hydrogenation of α-Substituted Acrylic Acids Catalyzed by a Ruthenocenyl Phosphino-oxazoline-Ruthenium Complex
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Asymmetric hydrogenation of various α-substituted acrylic acids was carried out using RuPHOX-Ru as a chiral catalyst under 5 bar H2, affording the corresponding chiral α-substituted propanic acids in up to 99% yield and 99.9% ee. The reaction could be performed on a gram-scale with a relatively low catalyst loading (up to 5000 S/C), and the resulting product (97%, 99.3% ee) can be used as a key intermediate to construct bioactive chiral molecules. The asymmetric protocol was successfully applied to an asymmetric synthesis of dihydroartemisinic acid, a key intermediate required for the industrial synthesis of the antimalarial drug artemisinin.
- Li, Jing,Shen, Jiefeng,Xia, Chao,Wang, Yanzhao,Liu, Delong,Zhang, Wanbin
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supporting information
p. 2122 - 2125
(2016/06/01)
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- A novel method for synthesis of α-keto esters with phenyliodine(III) diacetate
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A rapid and efficient synthesis of α-keto esters from β-ketonitriles using phenyliodine(III) diacetate is reported. This protocol gave α-keto esters in good yields. This is the first time to report the application of hypervalent iodine(III) reagents in the synthesis of α-keto esters. A plausible reaction mechanism is proposed.
- Xie, Yuanyuan,Liu, Jiwei,Huang, Yingyi,Yao, Lixia
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supporting information
p. 3793 - 3795
(2015/06/08)
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- Aryllithiums with increasing steric crowding and lipophilicity prepared from chlorides in diethyl ether. the first directly prepared room-temperature-stable dilithioarenes
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A convenient procedure has been developed for the preparation of synthetically useful, room-temperature-stable aryllithiums starting from aryl chlorides and lithium metal. The method provides a route to aryllithiums which have previously not been accessible cleanly or could only be prepared by using more expensive starting materials.
- Screttas, Constantinos G.,Steele, Barry R.,Micha-Screttas, Maria,Heropoulos, Georgios A.
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supporting information
p. 5680 - 5683
(2013/01/15)
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- Enantioselective enolate protonation in sulfamichael addition to r-substituted n-acryloyloxazolidin-2-ones with bifunctional organocatalyst
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Organocatalytic conjugate addition of thiols to R-substituted N-acryloyloxazolidin-2-ones followed by asymmetric protonation has been studied in the presence of cinchona alkaloid derived thioureas. Both of the enantiomers are accessible with the same level of enantioselectivity using pseudoenantiomeric quinine/quinidine derived catalysts. The addition/protonation products have been converted to useful biologically active molecules. 2011 American Chemical Society.
- Rana, Nirmal K.,Singh, Vinod K.
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supporting information; experimental part
p. 6520 - 6523
(2012/02/01)
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- An efficient oxidation of primary azides catalyzed by copper iodide: A convenient method for the synthesis of nitriles
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A wide range of primary azides have been efficiently oxidized by a catalytic amount of CuI and TBHP into their corresponding nitriles in aqueous solution. A variety of oxidizable functional groups were well tolerated under the reaction conditions, and oxidation of secondary azides furnished their corresponding ketones (see scheme; TBHP=tert-butyl hydroperoxide).
- Lamani, Manjunath,Prabhu, Kandikere Ramaiah
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supporting information; experimental part
p. 6622 - 6625
(2010/11/04)
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- Palladium-catalyzed [4 + 2] cycloaddition of o-(silylmethyl)benzyl esters with ketones: An equivalent to oxo-diels-alder reaction of o-xylylenes
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Figure Presented. o-(Silylmethyl)benzyl carbonates reacted with various electron-deficient ketones in the presence of a palladium catalyst, affording the [4 + 2] cycloaddition products, isochromanes, in high yields. The palladium-catalyzed cycloaddition i
- Ueno, Satoshi,Ohtsubo, Masakazu,Kuwano, Ryoichi
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supporting information; experimental part
p. 4332 - 4334
(2010/12/19)
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- CeCl3·7H2O: An effective additive in ru-catalyzed enantioselective hydrogenation of aromatic α-ketoesters
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(Chemical Equation Presented) In the presence of catalytic amounts of CeCl3·7H2O, [RuCl(benzene)(S)-SunPhos]Cl is a highly effective catalyst for the asymmetric hydrogenation of aromatic α-ketoesters. A variety of ethyl α-hydroxy-α-arylacetates have been prepared in up to 98.3% ee with a TON up to 10 000. Challenging aromatic α-ketoesters with ortho substituents are also hydrogenated with high enantioselectivities. The addition of CeCl3·7H2O not only improves the enantioselectivity but also enhances the stability of the catalyst. The ratio of CeCl3·7H2O to [RuCl(benzene)(S)-SunPhos]Cl plays an important role in the hydrogenation reaction with a large substrate/catalyst ratio.
- Meng, Qinghua,Sun, Yanhui,Ratovelomanana-Vidal, Virginie,Genet, Jean Pierre,Zhang, Zhaoguo
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p. 3842 - 3847
(2008/09/21)
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- Chiral N-heterocyclic carbene ligands for asymmetric catalytic oxindole synthesis
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The Pd-catalysed asymmetric intramolecular α-arylation of amide enolates containing heteroatom substituents gives chiral 3-alkoxy or 3-aminooxindoles in high yield and with enantioselectivities up to 97% ee when a new chiral N-heterocyclic carbene ligand is used. The Royal Society of Chemistry.
- Jia, Yi-Xia,Hillgren, J. Mikael,Watson, Emma L.,Marsden, Stephen P.,Kuendig, E. Peter
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supporting information; scheme or table
p. 4040 - 4042
(2009/03/11)
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- Manganese complexes of nitrogen-containing macrocyclic ligands effective as catalysts for dismutating superoxide
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The present invention is directed to low molecular weight mimics of superoxide dismutase (SOD) represented by the formula: STR1 wherein R, R', R1, R'1, R2, R'2, R3, R'3, R4, R'4, R5, R'5, R6, R'6, R7, R'7, R8, R'8, R9, and R'9 and X, Y, Z and n are as defined herein, useful as therapeutic agents for inflammatory disease states and disorders, ischemic/reperfusion injury, stroke, atherosclerosis, hypertension and all other conditions of oxidant-induced tissue damage or injury.
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- REARRANGEMENTS OF AROMATIC CARBONYL ARYLHYDRAZONES OF BENZENE, NAPHTHALENE, AND AZULENE
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Aromatic carbonyl arylhydrazones have been shown to undergo two kinds of rearrangement in polyphosphoric acid both involving nitrogen-nitrogen bond cleavage.The first proceeds via insertion of the imine portion in the position ortho to the second nitrogen atom to give o-phenylenediamine intermediates: their evolution depends on the nature of the starting substrate.This reaction has been employed for synthesizing the quinoxalines (5) and the phenanthridines (11), and was demonstrated to be intramolecular.The second reaction path is a sigmatropic rearrangment exclusive to electron-rich aromatic carbonyl hydrazones.
- Benincori, Tiziana,Pagani, Silvia Bradamante,Fusco, Raffaello,Sannicolo, Franco
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p. 2721 - 2728
(2007/10/02)
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- &α,&α-Difluoroarylacetic Acids: Preparation from (Diethylamino)sulfur Trifluoride and &α-Oxoarylacetates
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Several α,α-difluoroarylacetic acids have been prepared by reaction of DAST ((diethylamino)sulfur trifluoride) with esters of α-oxoarylacetic acids and then hydrolysis of the resulting difluoro ester.Examples include the α,α-difluoro derivates of the synthetic plant auxin, α-naphthylacetic acid, and the antiinflammatory drug, ibufenac.
- Middleton, W. J.,Bingham, E. M.
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p. 2883 - 2887
(2007/10/02)
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