34966-49-9Relevant academic research and scientific papers
Tandem Photoredox-Chiral Phosphoric Acid Catalyzed Radical-Radical Cross-Coupling for Enantioselective Synthesis of 3-Hydroxyoxindoles
Zhang, Yang,Ye, Dan,Shen, Lei,Liang, Kangjiang,Xia, Chengfeng
supporting information, p. 7112 - 7117 (2021/09/14)
A photochemical protocol that couples diarylamines and α-ketoesters to afford the chiral 3-hydroxyoxindoles through tandem photoredox and chiral phosphoric acid catalysis is developed. The reaction involves an enantioselective photochemical radical-radical cross-coupling process. The chiral phosphoric acid is discovered to play crucial roles by decreasing the reductive potentials of α-ketoesters and stereocontrolling the downstream asymmetric radical-radical cross-coupling via the formation of pentacoordinate complex.
Divergent Photocatalytic Reactions of α-Ketoesters under Triplet Sensitization and Photoredox Conditions
Dong, Xiao,Yoon, Tehshik P.,Zheng, Jian
, (2020/09/02)
The long-lived triplet excited states of transition metal photocatalysts can activate organic substrates via either energy- or electron-transfer pathways, and the rates of these processes can be influenced by rational tuning of the reaction conditions. The characteristic reactive intermediates generated, however, are distinct and can exhibit very different reactivity patterns. This mechanistic diversity available to photocatalytic reactions might thus offer an opportunity to engineer divergent reactions that give markedly different chemical outcomes under superficially similar conditions. Herein, we show that the photocatalytic reactions of benzoylformate esters with alkenes can be directed toward either Paternò-Büchi cycloadditions or allylic functionalization reactions under conditions favoring energy transfer or electron transfer, respectively. These studies provide a framework for designing other divergent photocatalytic methods that produce different sets of reaction outcomes under photoredox and triplet sensitization conditions.
Synthetic method of racemic clopidogrel
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Paragraph 0031-0033; 0036-0037; 0042-0044, (2020/09/12)
The invention relates to a synthesis method of racemic clopidogrel, which comprises the following steps: 1) uniformly mixing methyl benzoylformate, N-chlorosuccinimide, palladium acetate, a ligand andtrifluoroacetic acid, and carrying out ortho-chlorinati
Novel synthesis method of alpha-carbonyl acid ester
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, (2020/07/21)
The invention discloses a novel synthesis method of alpha-carbonyl acid ester. The method comprises the following steps: carrying out chlorination reaction on an alpha-methylene-containing nitrile compound and chlorine to obtain dichloronitrile, reacting the dichloronitrile product in a sulfuric acid and water system to obtain formyl cyanide, then acquiring an imino sulfate compound in the same reaction system, and finally performing esterification to obtain the target product. The adopted reaction raw materials are wide in sources and low in price, highly toxic solid sodium cyanide can be prevented from being used in the prior art, the method is environmentally friendly, and the method is easy to operate, mild in condition and easy to industrialize.
Carbene-Catalyzed Enantioselective Aromatic N-Nucleophilic Addition of Heteroarenes to Ketones
Liu, Yonggui,Luo, Guoyong,Yang, Xing,Jiang, Shichun,Xue, Wei,Chi, Yonggui Robin,Jin, Zhichao
supporting information, p. 442 - 448 (2019/11/25)
The aromatic nitrogen atoms of heteroarylaldehydes are activated by carbene catalysts to react with ketone electrophiles. Multi-functionalized cyclic N,O-acetal products are afforded in good to excellent yields and optical purities. Our reaction involves the formation of an unprecedented aza-fulvene-type acylazolium intermediate. A broad range of N-heteroaromatic aldehydes and electron-deficient ketone substrates works effectively in this transformation. Several of the chiral N,O-acetal products afforded through this protocol exhibit excellent antibacterial activities against Ralstonia solanacearum (Rs) and are valuable in the development of novel agrichemicals for plant protection.
Method for preparing spiro beta-lactam
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Paragraph 0048-0051, (2020/07/12)
The invention discloses a method for preparing spiro beta-lactam. The method comprises the following step: carrying out [2+1] cyclization reaction on beta-lactam and keto ester under the condition ofa phosphine catalyst to generate spiro beta-lactam. The
Pd(OAc)2-Catalyzed Asymmetric Hydrogenation of α-Iminoesters
Chen, Jianzhong,Li, Feilong,Wang, Fang,Hu, Yawen,Zhang, Zhenfeng,Zhao, Min,Zhang, Wanbin
supporting information, p. 9060 - 9065 (2019/11/19)
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.
CuO-catalyzed oxidation of aryl acetates with aqueous tert-butyl hydroperoxide for the synthesis of α-ketoesters
Jiang, Jin
, p. 235 - 240 (2019/07/16)
A practical method to access α-ketoesters from readily available aryl acetates is developed. In this approach, aqueous tert-butyl hydroperoxide and CuO are employed. No additional solvents are required and it was found that the peroxide side products in the reaction can be decomposed by pyridine.
Template-Directed Synthesis of Photocatalyst-Encapsulating Metal-Organic Frameworks with Boosted Photocatalytic Activity
Yang, Xiaojie,Liang, Tao,Sun, Jiaxing,Zaworotko, Michael J.,Chen, Yao,Cheng, Peng,Zhang, Zhenjie
, p. 7486 - 7493 (2019/08/26)
In the past decade, the use of visible light to promote organic transformations has gained intense attention. In this study, we developed a template-directed synthesis method to use homogeneous Ru and Ir photocatalysts as structure-directing templates and succeeded to prepare a series of photocatalyst-encapsulating metal-organic frameworks (photocatalyst@MOFs) with zeolite-like structures. The open channels and polyhedral cages of MOFs effectively dispersed the encapsulated photocatalysts and facilitated the transport of reactants and products, leading to boosted catalytic activity and good reusability toward important organic reactions such as aerobic oxidation reaction of benzyl halides and the cyclization of tertiary anilines and maleimides under visible light. Moreover, we also demonstrate the versatility and universality of our templating strategy. It not only can form MOFs which cannot be accessed by other synthesis methods, but also can encapsulate various commercially available homogeneous photocatalysts into MOFs. This work explores an avenue to prepare heterogeneous photocatalysts to catalyze value-added reactions.
Copper catalyzed photoredox synthesis of α-keto esters, quinoxaline, and naphthoquinone: Controlled oxidation of terminal alkynes to glyoxals
Das, Deb Kumar,Kumar Pampana, V. Kishore,Hwang, Kuo Chu
, p. 7318 - 7326 (2018/10/15)
Herein, we report a facile visible light induced copper catalyzed controlled oxidation of terminal CC alkynes to α-keto esters and quinoxalines via formation of phenylglyoxals as stable intermediates, under mild conditions by using molecular O2 as a sustainable oxidant. The current copper catalysed photoredox method is simple, highly functional group compatible with a broad range of electron rich and electron poor aromatic alkynes as well as aliphatic alcohols (1°, 2° and 3° alcohols), providing an efficient route for the preparation of α-keto esters (43 examples), quinoxaline and naphthoquinone with higher yields than those in the literature reported thermal processes. Furthermore, the synthetic utility of the products has been demonstrated in the synthesis of two biologically active molecules, an E. coli DHPS inhibitor and CFTR activator, using the current photoredox process. In addition, we applied this methodology to the one-pot synthesis of a heterocyclic compound (quinoxaline, an FLT3 inhibitor) by trapping the intermediate phenylglyoxal with O-phenylenediamine. The intermediate phenylglyoxal can also be isolated and further reacted with an internal alkyne to form naphthoquinone. This process can be readily scaled up to the gram scale.
