- Hypervalent Iodine(III)-Promoted Radical Oxidative C-H Annulation of Arylamines with α-Keto Acids
-
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
-
supporting information
p. 12084 - 12092
(2021/08/24)
-
- Visible-Light-Promoted Switchable Synthesis of C-3-Functionalized Quinoxalin-2(1H)-ones
-
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
-
supporting information
p. 1443 - 1448
(2021/01/26)
-
- K2S2O8activation by glucose at room temperature for the synthesis and functionalization of heterocycles in water
-
While persulfate activation at room temperature using glucose has primarily been focused on kinetic studies of the sulfate radical anion, the utilization of this protocol in organic synthesis is rarely demonstrated. We reinvestigated selected K2S2O8-mediated known organic reactions that invariably require higher temperatures and an organic solvent. A diverse, mild functionalization and synthesis of heterocycles using the inexpensive oxidant K2S2O8 in water at room temperature is reported, demonstrating the sustainability and broad scope of the method. Unlike traditional methods used for persulfate activation, the current method uses naturally abundant glucose as a K2S2O8 activator, avoiding the use of higher temperature, UV light, transition metals or bases.
- Hunjan, Mandeep Kaur,Laha, Joydev K.
-
supporting information
p. 8437 - 8440
(2021/09/02)
-
- Diazotrifluoroethyl Radical: A CF3-Containing Building Block in [3 + 2] Cycloaddition
-
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
-
supporting information
p. 9256 - 9261
(2021/12/06)
-
- General Synthesis of Chiral α,α-Diaryl Carboxamides by Enantioselective Palladium-Catalyzed Cross-Coupling
-
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
-
p. 4974 - 4978
(2020/07/03)
-
- Novel synthesis method of benzene ring polysubstituted compound based on benzoyl formic acid
-
The invention relates to a novel synthesis method of a benzene ring polysubstituted compound based on benzoyl formic acid. According to the synthesis method, an acetophenone-based benzene ring polysubstituted compound is used as a raw material, a specific
- -
-
Paragraph 0027-0033; 0195-0204
(2020/05/30)
-
- Aroylation of Electron-Rich Pyrroles under Minisci Reaction Conditions
-
The development of Minisci acylation on electron-rich pyrroles under silver-free neutral conditions has been reported featuring the regioselective monoacylation of (NH)-free pyrroles. Unlike conventional Minisci conditions, the avoidance of any acid that could result in the polymerization of pyrroles was the key to success. The umpolung reactivity of the nucleophilic acyl radical, generated in situ from arylglyoxylic acid, could help explain the mechanism of product formation with electron-rich pyrroles. Alternatively, the nucleophilic substitution of the acyl radical on the electron-deficient pyrrole radical cation is proposed.
- Laha, Joydev K.,Kaur Hunjan, Mandeep,Hegde, Shalakha,Gupta, Anjali
-
supporting information
p. 1442 - 1447
(2020/02/22)
-
- Selective photoredox decarboxylation of α-ketoacids to allylic ketones and 1,4-dicarbonyl compounds dependent on cobaloxime catalysis
-
A photoredox/cobaloxime co-catalyzed coupling reaction of α-ketoacids and methacrylates to obtain allylic ketones is described. Without the cobaloxime catalyst, 1,4-dicarbonyl compounds are generated. The cobaloxime catalyst enables dehydrogenation to generate the formation of new olefins. The generality, good substrate scope and mild conditions are good features in the photoredox/cobaloxime catalysis protocol, and this method will provide new opportunities for the functionalization of more olefins.
- Zhang, Hong,Xiao, Qian,Qi, Xu-Kuan,Gao, Xue-Wang,Tong, Qing-Xiao,Zhong, Jian-Ji
-
supporting information
p. 12530 - 12533
(2020/11/02)
-
- Photoredox Catalysis Enables Decarboxylative Cyclization with Hypervalent Iodine(III) Reagents: Access to 2,5-Disubstituted 1,3,4-Oxadiazoles
-
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
-
supporting information
p. 9621 - 9626
(2020/12/21)
-
- METHOD FOR PRODUCING BENZOYL FORMIC ACID COMPOUND AND PYRIDAZINE COMPOUND
-
The present invention provides an industrially-advantageous process for preparing a benzoyl formic acid compound, and an efficient process for preparing a pyridazine compound using the same process. Specifically, the present invention provides a process for preparing a compound represented by formula (2), which comprises a step (B): a step of reacting a compound represented by formula (1) with a nitrosyl sulfuric acid in water to produce the compound represented by formula (2).
- -
-
Paragraph 0100
(2020/12/18)
-
- Studies on the L-2-hydroxy-acid oxidase 2 catalyzed metabolism of S-mandelic acid and its analogues
-
Mandelic acid (MA) is generally used as a biomarker of the exposure of styrene, which is classified as a class of hazardous environmental pollutants, and also used as an important chiral intermediate in pharmaceutical industry. The previous studies have found the excretion of phenylglyoxylic acid (PGA) in human and rat, a metabolite of MA, was mainly from S-MA rather than R-MA. The metabolic mechanism, however, is not clear. In order to explore the possible metabolic mechanism, the enzyme types involved in the stereoselectivity metabolism of MA were firstly studied, and then human and rat long-chain 2-hydroxy-acid oxidase 2 (HAO2) were recombinantly expressed to study the metabolic profiles of S-MA and its analogues. The results indicated that HAO2 might catalyze the stereoselectivity metabolism of S-MA in rats. Human HAO2 (hHAO2) and rat HAO2 (rHAO2) isozymes β1 and β2 were successfully cloned and expressed with high purity and good enzyme activities. The enzyme kinetic profiles of these enzymes were different for S-MA and analogues. The order of catalytic efficiency for hHAO2 and rHAO2, however, was reverse. It might be relevance to the difference in active amino acid residues and loop 4 in human and rat L-2-hydroxy acid oxidase isozyme B crystal structures.
- Zhang, Yang,Su, Chen,Lei, Jinxiu,Chen, Lu,Hu, Haihong,Zeng, Su,Yu, Lushan
-
p. 187 - 193
(2019/03/14)
-
- Pd(OAc)2-Catalyzed Asymmetric Hydrogenation of α-Iminoesters
-
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
-
supporting information
p. 9060 - 9065
(2019/11/19)
-
- Umpolung Reactivity of Aldehydes toward Carbon Dioxide
-
Carbon dioxide is an intrinsically stable molecule. Therefore, its activation requires extra energy input in the form of reactive reagents and/or activated catalysts and, often, harsh reaction conditions. Reported here is a direct carboxylation reaction of aromatic aldehydes with carbon dioxide to afford α-keto acids as added-value products. In situ generation of a reactive cyanohydrin was the key to the successful carboxylation reaction under operationally mild reaction conditions (25–40 °C, 1 atm CO2). The resulting α-keto acids served as a platform for α-amino acid synthesis by reductive amination reactions, illustrating the chemical synthesis of essential bioactive molecules from carbon dioxide.
- Juhl, Martin,Lee, Ji-Woong
-
supporting information
p. 12318 - 12322
(2018/09/10)
-
- Direct Acyl Radical Addition to 2 H-Indazoles Using Ag-Catalyzed Decarboxylative Cross-Coupling of α-Keto Acids
-
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
-
supporting information
p. 2711 - 2715
(2018/05/22)
-
- Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
-
Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes. (Figure presented.).
- Meng, Mengting,Wang, Guofang,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
-
supporting information
p. 1218 - 1231
(2018/02/16)
-
- Silver-catalyzed decarboxylative cross-coupling of α-keto acids with alkenes giving approach to chalcones
-
A silver-catalyzed decarboxylative cross-coupling of α-keto acids with alkenes is reported. The method, with a wide range of substrate tolerance and mild operational conditions, can produce various chalcone derivatives in moderate to high yields from easily available starting materials.
- Wu, Shang,Yu, Hongheng,Hu, Qinzheng,Yang, Quanlu,Xu, Shouwang,Liu, Tian
-
supporting information
p. 4763 - 4765
(2017/12/01)
-
- Enzymatic Resolution by a d-Lactate Oxidase Catalyzed Reaction for (S)-2-Hydroxycarboxylic Acids
-
Oxidase-catalyzed kinetic resolution is important for the production of enantiopure 2-hydroxycarboxylic acids (2-HAs), which are versatile building blocks for the synthesis of many significant compounds. However, in contrast to that of (R)-2-HAs, the production of (S)-2-HA is challenging because of the lack of related oxidases. Herein, suitable enzymes were screened systematically through the analysis of numerous putative d-lactate oxidase sequences and identification of several required properties. Finally, a d-lactate oxidase from Gluconobacter oxydans 621H with advantageous characteristics, such as good solubility, broad substrate spectrum, and high stereoselectivity, was selected to resolve 2-HAs into (S)-2-HAs. A variety of (S)-2-HAs was produced successfully using this d-lactate oxidase with excellent enantiomeric excess values (>99 %). The presented screening criteria and approach for target biocatalysis suggested a guideline for the production of optically active chemicals such as (S)-2-HAs.
- Sheng, Binbin,Xu, Jing,Ge, Yongsheng,Zhang, Shuo,Wang, Danqi,Gao, Chao,Ma, Cuiqing,Xu, Ping
-
p. 2630 - 2633
(2016/08/30)
-
- Asymmetric Hydrogenation of α-Substituted Acrylic Acids Catalyzed by a Ruthenocenyl Phosphino-oxazoline-Ruthenium Complex
-
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
-
supporting information
p. 2122 - 2125
(2016/06/01)
-
- Catalyst-Free Singlet Oxygen-Promoted Decarboxylative Amidation of α-Keto Acids with Free Amines
-
A novel catalyst-free decarboxylative amidation of α-keto acids with amines under mild conditions has been developed. Advantages of the new protocol include avoidance of metal catalysts and high levels of functional group tolerance. In addition, the reaction can be scaled up and shows high chemoselectivity. Preliminary mechanistic studies suggest that singlet oxygen, generated from oxygen under irradiation, is the key promoter for this catalyst-free transformation.
- Xu, Wen-Tao,Huang, Bei,Dai, Jian-Jun,Xu, Jun,Xu, Hua-Jian
-
supporting information
p. 3114 - 3117
(2016/07/14)
-
- Synthesis of oxazoles by silver catalysed oxidative decarboxylation-cyclization of α-oxocarboxylates and isocyanides
-
A silver catalysed synthesis of oxazoles by the oxidative decarboxylation-cyclization of α-oxocarboxylates and isocyanides was developed. This method provided a novel strategy to construct oxazole rings compared to traditional methods. Mechanistic investigations such as operando IR, EPR and radical inhibition experiments were carefully done and confirmed the acyl cation and Ag(ii) as the intermediates in this transformation, and the involvement of a radical decarboxylative process.
- Ma, Yiyang,Yan, Zhiyuan,Bian, Changliang,Li, Ke,Zhang, Xiaowen,Wang, Mengfan,Gao, Xinlong,Zhang, Heng,Lei, Aiwen
-
supporting information
p. 10524 - 10527
(2015/06/25)
-
- Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
-
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
-
p. 15987 - 15990
(2015/02/19)
-
- Enantio- and chemoselective Br?nsted-acid/Mg(nBu) 2 catalysed reduction of α-keto esters with catecholborane
-
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
-
supporting information
p. 4489 - 4491
(2014/04/17)
-
- Chemo- and enantioselective Bronsted acid-catalyzed reduction of α-imino esters with catecholborane
-
The chemo- and enantioselective reduction of α-imino esters with catecholborane has been developed employing 10 mol% of an enantiopure BINOL-based phosphoric acid as organocatalyst. Various differently substituted aromatic α-amino acid derivatives can be
- Enders, Dieter,Rembiak, Andreas,Stoeckel, Bianca Anne
-
supporting information
p. 1937 - 1942
(2013/08/23)
-
- Palladium-catalyzed decarboxylative acylation of O-methyl ketoximes with α-keto acids
-
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
-
supporting information
p. 925 - 927
(2013/02/23)
-
- Cu(ii)-catalyzed decarboxylative acylation of acyl C-H of formamides with α-oxocarboxylic acids leading to α-ketoamides
-
CuBr2-catalyzed decarboxylative acylation of the acyl C-H of N-monosubstituted and N,N-disubstituted formamides with α-oxocarboxylic acids leading to α-ketoamides was developed, which generated the corresponding products in good yields. The Royal Society of Chemistry 2013.
- Li, Dengke,Wang, Min,Liu, Jie,Zhao, Qiong,Wang, Lei
-
supporting information
p. 3640 - 3642
(2013/05/21)
-
- Copper-promoted decarboxylative direct C3-acylation of N-substituted indoles with α-oxocarboxylic acids
-
A novel and efficient Cu-promoted decarboxylative direct C3-acylation of N-substituted indoles with α-oxocarboxylic acids for the synthesis of 3-acylindoles was developed. The Royal Society of Chemistry.
- Yu, Lin,Li, Pinhua,Wang, Lei
-
supporting information
p. 2368 - 2370
(2013/06/27)
-
- Decarboxylative acylation of cyclic enamides with α-oxocarboxylic acids by palladium-catalyzed C-H activation at room temperature
-
An efficient catalytic decarboxylative acylation of unactivated sp 2 (alkenyl) C-H bonds has been developed. Various substituted α-oxocarboxylic acids with different electronic properties react under mild conditions to afford a diverse range of β-acyl enamide products in good yields. The reaction is proposed to proceed via a cyclic vinylpalladium intermediate, facilitating the decarboxylative dehydrogenative process with enamide coupling partners.
- Wang, Hua,Guo, Li-Na,Duan, Xin-Hua
-
supporting information
p. 4358 - 4361
(2012/10/29)
-
- Room temperature palladium-catalyzed decarboxylative ortho -acylation of acetanilides with α-oxocarboxylic acids
-
A novel Pd-catalyzed decarboxylative ortho-acylation of acetanilides with α-oxocarboxylic acids is realized at room temperature. This reaction provides efficient access to o-acyl acetanilides under mild conditions.
- Fang, Ping,Li, Mingzong,Ge, Haibo
-
experimental part
p. 11898 - 11899
(2010/11/02)
-
- Asymmetrie aerobic oxidation of α-hydroxy acid derivatives by C 4-symmetric, vanadate-centered, tetrakisvanadyl(V) clusters derived from N-salicylidene-α-aminocarboxylates
-
(Chemical Equation Presented) A series of chiral vanadyl(V) methoxides bearing 3-t-butyl-5-substituted N-salicylene-L-valinate and L-t-leucinate as chiral auxiliaries has been prepared. In all cases except the 3,5-di-t-butyl analogue, they exist as monomers both in solution and in the single crystal state. In the case of the 3,5-di-t-butyl analogue, the architectural nature of the vanadyl(V) complex highly depends on the base used during the complex formation event. A pentanuclear C4-symmetric complex was formed when potassium salts were employed instead of the corresponding sodium salts. A central vanadate(V) unit serves to grip four identical chiral monomelic vanadyl(V) units together, by which a potassium ion sits on top of the four flanking units through carbonyl coordinations and serves to hold the whole cluster by cooperation with the central vanadate(V) unit. In comparison with the corresponding monomelic vanadyl(V) methoxide complex, the cluster complex was utilized to facilitate the asymmetric aerobic oxidations of various racemic α-hydroxyesters, -amides, and -thioesters with excellent selectivity factors (krel 40 to >500).
- Chen, Chien-Tien,Bettigeri, Sampada,Weng, Shiue-Shien,Pawar, Vijay D.,Lin, Ya-Hui,Liu, Cheng-Yuan,Lee, Way-Zen
-
p. 8175 - 8185
(2008/02/13)
-
- Method for producing optically active mandelic acid derivatives
-
The present invention provides a method for enzymatically producing optically active mandelic acid derivatives. An optically active mandelic acid derivative (shown as Formula II) is produced by reacting a culture or cell body of a microorganism, or processed products thereof, with a phenylglyoxylic acid derivative, and then recovering the obtained optically active mandelic acid derivative, wherein the microorganism has the ability to stereo-selectively reduce the phenylglyoxylic acid derivative. An optically active mandelic acid obtained according to the present invention is useful as an intermediate for the synthesis of pharmaceuticals and agricultural chemicals.
- -
-
Page column 13
(2008/06/13)
-