- 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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p. 8645 - 8649
(2021/10/25)
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- Palladium-catalyzed cascade synthesis of spirocyclic oxindoles via regioselective C2-H arylation and C8-H alkylation of naphthalene ring
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A simultaneous C2-H arylation and C8-H alkylation of naphthalene ring has been achieved by palladium-catalyzed cascade reaction of N-(2-halophenyl)-2-(naphthalen-1-yl)acrylamides with aryl iodides, which provides an efficient method for synthesizing various aryl-substituted spirocyclic oxindoles. The protocol enables three C–C bonds formation via an intramolecular Heck reaction and sequentially regioselective C–H bond activation.
- Luo, Xiai,Li, Wenguang,Lu, Haiyan,Deng, Guobo,Yang, Yuan,Yang, Chunming,Liang, Yun
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supporting information
p. 713 - 716
(2020/07/24)
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- Synthesis of Cyclopentenones through Rhodium-Catalyzed C-H Annulation of Acrylic Acids with Formaldehyde and Malonates
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An efficient rhodium-catalyzed protocol for the synthesis of cyclopentenones based on a three-component reaction of acrylic acids, formaldehyde, and malonates via vinylic C-H activation is reported. Exploratory studies showed that 5-alkylation of as-prepared cyclopentenones could be realized smoothly by the treatment of a variety of alkyl halides with a Na2CO3/MeOH solution. Excess formaldehyde and malonate led to a multicomponent reaction that afforded the multisubstituted cyclopentenones through a Michael addition.
- Yu, Shuling,Hong, Chao,Liu, Zhanxiang,Zhang, Yuhong
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supporting information
p. 5054 - 5059
(2021/07/20)
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- Cobalt-Catalyzed Vinylic C-H Addition to Formaldehyde: Synthesis of Butenolides from Acrylic Acids and HCHO
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A carboxyl-assisted C-H functionalization of acrylic acids with formaldehyde to give butenolides is described. It is the first time that the addition of an inert vinylic C-H bond to formaldehyde has been achieved via cobalt-catalyzed C-H activation. The unique reactivity of the cobalt species was observed when compared with related Rh or Ir catalysts. γ-Hydroxymethylated butenolides were produced by the treatment of Na2CO3 after the catalytic reaction in one pot.
- Yu, Shuling,Hong, Chao,Liu, Zhanxiang,Zhang, Yuhong
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supporting information
p. 8359 - 8364
(2021/11/01)
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- Electrochemical oxidative: Z -selective C(sp2)-H chlorination of acrylamides
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An electrochemical method for the oxidative Z-selective C(sp2)-H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was demonstrated through chemoselective transformations and the electrochemical process was performed on gram scale in flow.
- Coles, Simon J.,Hareram, Mishra Deepak,Harnedy, James,Morrill, Louis C.,Tizzard, Graham J.
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supporting information
p. 12643 - 12646
(2021/12/07)
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- Palladium-Catalyzed Highly Regioselective Hydrocarboxylation of Alkynes with Carbon Dioxide
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A Pd-catalyzed highly regioselective hydrocarboxylation of alkynes with carbon dioxide has been established. By the combination of Pd(PPh3)4 and 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (binap), a variety of functionalized alkynes, including aryl alkynes, aliphatic alkynes, propargylamines, and propargyl ethers, could be leveraged to provide a wide array of α-acrylic acids in high yields with high regioselectivity under mild reaction conditions. Experimental and DFT mechanistic studies revealed that this reaction proceeded via the cyclopalladation process of alkynes and carbon dioxide in the presence of binap to generate a five-membered palladalactone intermediate and enabled the formation of Markovnikov adducts. Moreover, this strategy provided an effective method for the late-stage functionalization of alkyne-containing complicated molecules, including natural products and pharmaceuticals.
- Chen, Pengquan,Cheng, Ruixiang,Jiang, Huanfeng,Lei, Ming,Lou, Hongming,Qi, Chaorong,Shi, Fuxing,Wang, Lu,Wu, Wanqing,Xiong, Wenfang,Zhu, Baiyao
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p. 7968 - 7978
(2020/08/21)
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- Macrolactam Synthesis via Ring-Closing Alkene-Alkene Cross-Coupling Reactions
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Reported herein is a practical method for macrolactam synthesis via a Rh(III)-catalyzed ring closing alkene-alkene cross-coupling reaction. The reaction proceeded via a Rh-catalyzed alkenyl sp2 C-H activation process, which allows access to macrocyclic molecules of different ring sizes. Macrolactams containing a conjugated diene framework could be easily prepared in high chemoselectivities and Z,E stereoselectivities.
- Goh, Jeffrey,Loh, Teck-Peng,Maraswami, Manikantha
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supporting information
p. 9724 - 9728
(2020/12/21)
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- A 1,3,2-Diazaphospholene-Catalyzed Reductive Claisen Rearrangement
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1,3,2-Diazaphospholenes (DAPs) are an emerging class of organic hydrides. In this work, we exploited them as efficient catalysts for very mild reductive Claisen rearrangements. The method is tolerant towards a wide variety of functional groups and operates at ambient temperature. Besides being enantiospecific for substrates with existing stereogenic centers, the diastereoselectivity can be switched by varying solvents and DAP catalysts. The reaction kinetics show direct rearrangements of O-bound phospholene enolates and provide a proof-of-principle for catalytic enantioselective reactions.
- Reed, John H.,Donets, Pavel A.,Miaskiewicz, Solène,Cramer, Nicolai
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supporting information
p. 8893 - 8897
(2019/05/28)
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- Macrolide Synthesis through Intramolecular Oxidative Cross-Coupling of Alkenes
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A RhIII-catalyzed intramolecular oxidative cross-coupling between double bonds for the synthesis of macrolides is described. Under the optimized reaction conditions, macrocycles containing a diene moiety can be formed in reasonable yields and with excellent chemo- and stereoselectivity. This method provides an efficient approach to synthesize macrocyclic compounds containing a 1,3-conjugated diene structure.
- Jiang, Bing,Zhao, Meng,Li, Shu-Sen,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 555 - 559
(2018/02/21)
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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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p. 2869 - 2872
(2017/06/13)
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- Water as a Hydride Source in Palladium-Catalyzed Enantioselective Reductive Heck Reactions
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Pd-catalyzed intramolecular asymmetric carbopalladation of N-aryl acrylamides followed by reduction of C(sp3)-Pd intermediate using diboron–water as a hydride source afforded enantioenriched 3,3-disubstituted oxindoles in high yields and enantioselectivities. When heavy water was used as a deuterium donor in combination with bis(catecholato)diboron (Cat2B2), deuterium was incorporated into the products with high synthetic efficiency. The ligand determined both the enantioselectivity of the reaction and the reaction pathways, thereby affording either hydroarylation (reductive Heck) or carboborylation products.
- Kong, Wangqing,Wang, Qian,Zhu, Jieping
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supporting information
p. 3987 - 3991
(2017/03/27)
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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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p. 2122 - 2125
(2016/06/01)
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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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p. 6520 - 6523
(2012/02/01)
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- Enantioselective [3 + 2] cycloaddition of allenes to acrylates catalyzed by dipeptide-derived phosphines: Facile creation of functionalized cyclopentenes containing quaternary stereogenic centers
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A new family of dipeptide-based chiral phosphines was designed and prepared. d-Thr-l-tert-Leu-derived catalyst 4c promoted [3 + 2] cycloaddition of allenoates to α-substituted acrylates in a regiospecific and stereoselective manner, furnishing functionalized cyclopentenes with quaternary stereogenic centers in high yields and with excellent enantioselectivities.
- Han, Xiaoyu,Wang, Youqing,Zhong, Fangrui,Lu, Yixin
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supporting information; experimental part
p. 1726 - 1729
(2011/04/17)
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- Toward an optimal joint recognition of the s1′ subsites of endothelin converting enzyme-1 (ECE-1), angiotensin converting enzyme (ACE), and neutral endopeptidase (NEP)
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The formation of vasoconstrictors (e.g., angiotensin II and endothelin) and the inactivation of vasodilators (e.g., bradykinin and atrial natriuretic) by membrane-bound zinc metallopeptidases are key mechanisms in the control of blood pressure and fluid h
- Inguimbert, Nicolas,Coric, Pascale,Poras, Hervé,Meudal, Hervé,Teffot, Franck,Fournié-Zaluski, Marie-Claude,Roques, Bernard P.
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p. 1477 - 1486
(2007/10/03)
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- Isoxazole compounds useful for the prophylaxis or treatment of nervous diseases
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Isoxazole compounds having the following general formula: STR1 wherein R1 represents an optionally substituted aryl group or aromatic heterocyclic group; R2 represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, a cyano group, a carboxyl group, an alkanoyl group, an alkoxycarbonyl group or an optionally substituted carbamoyl group; R3 represents an optionally substituted amino group or a saturated heterocyclic group; X represents an oxygen atom or a sulfur atom; and n is an integer of from 2 to 6. These compounds have excellent monoamine oxidase inhibitory activity and are useful as a therapeutic agent or a preventive agent against nervous diseases such as depression.
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- Monomeric compounds
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Photosensitive homopolymers and substantially non-crosslinked copolymers containing the recurring unit: EQU1 R1 may be substituted or unsubstituted alkylene, aralkylene, alkoxyalkylene or aryloxyalkylene. R2 is a substituted or unsubstituted aryl group or heterocyclic group having aromatic character. R3, R4, and R5 are hydrogen, halogen or lower alkyl. R6 and R7 may be hydrogen, halogen, nitro, lower alkyl, phenyl, substituted phenyl, phenoxy and lower alkoxy. Lithographic plates bearing these photosensitive polymers can be stored without deterioration for extended periods prior to exposure, and produce highly abrasion resistant plates on being exposed. The photosensitive polymers of the invention are preferably produced by homopolymerization of novel monomers having the general formula EQU2 where R1 ' is alkylene, haloalkylene, alkoxyalkylene, aminoalkylene, cycloalkylene, aralkylene, cycloalkylalkylene, cyanoalkylene, and aryloxyalkylene, and R2, R3, R4, R5, R6, and R7 are as defined above; and by copolymerization of these monomers with one or more ethylenically unsaturated comonomers. Methods of preparing the photopolymers and the novel monomers are also disclosed, as are methods of preparing and exposing plates bearing the polymers.
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