5180-78-9Relevant academic research and scientific papers
Copper on charcoal: Cu0nanoparticle catalysed aerobic oxidation of α-diazo esters
Chu, Changhu,Dong, Wenwen,Lin, Jia,Teng, Jiangge,Wang, Zhiwei,Zhao, Rong
, p. 6120 - 6126 (2021/07/21)
By using a charcoal supported nano Cu0catalyst (Cu/C), a highly efficient oxidation of α-diazo esters to α-ketoesters with molecular oxygen as the sole oxidant has been developed. In the presence of the Cu/C catalyst, 2-aryl-α-diazo esters with both electron-donating and electron-withdrawing groups can be oxidized to the corresponding α-ketoesters efficiently. Furthermore, this Cu/C catalyst can catalyse the reaction of aryl α-diazo ester with water to form aryl ketoester, 2-aryl-2-hydroxyl acetate ester and 2-aryl acetate ester. In this case, water is split by α-diazo ester, and the diazo group is displaced by the oxygen or hydrogen atom in water. Mechanistic investigation showed that the reaction of α-diazo ester with oxygen proceeds through a radical pathway. In the presence of 2,2,6,6-tetramethyl piperidine nitrogen oxide, the reaction of α-diazo ester with oxygen is dramatically inhibited. Furthermore, the reaction of α-diazo ester with water is investigated by an isotopic tracer method, and GCMS detection showed that a disproportionation reaction occurred between α-diazo ester and water.
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.
Visible-Light-Induced Catalyst-Free Carboxylation of Acylsilanes with Carbon Dioxide
Fan, Zhengning,Yi, Yaping,Chen, Shenhao,Xi, Chanjuan
, p. 2303 - 2307 (2021/04/05)
Intermolecular carbon-carbon bond formation between acylsilanes and carbon dioxide (CO2) was achieved by photoirradiation under catalyst-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of the acylsilanes added to the C═O bond of CO2 to give α-ketocarboxylates, which underwent hydrolysis to afford α-ketocarboxylic derivatives in good yields. Control experiments suggest that the generated siloxycarbene is likely to be from the singlet state (S1) of the acylsilane and the addition to CO2 is not in a concerted manner.
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
Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
Yan, Pu-Cha,Xie, Jian-Hua,Zhang, Xiang-Dong,Chen, Kang,Li, Yuan-Qiang,Zhou, Qi-Lin,Che, Da-Qing
supporting information, p. 15987 - 15990 (2015/02/19)
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.
Asymmetrie aerobic oxidation of α-hydroxy acid derivatives by C 4-symmetric, vanadate-centered, tetrakisvanadyl(V) clusters derived from N-salicylidene-α-aminocarboxylates
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)
(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).
Vanadium-catalysed Novel Oxidation of Arylacetic Esters for the Synthesis of Arylglyoxylic Esters
Choudary, B. M.,Reddy, G. Vidya Sagar,Rao, K. Koteswara
, p. 323 - 324 (2007/10/02)
Direct synthesis of arylglyoxylic esters in excellent yields from inexpensive arylacetic esters is realised for the first time by the oxidation of activated methylene using vanadium pillared clay as the catalyst and tert-butylhydroperoxide as an oxidant.
Syntheses of Aryl Glyoxylate. I. The Reaction of Alkyl Dichloro(alkoxy)acetates with Aromatics in the Presence of Lewis Acid
Itoh, Osamu,Nagata, Takayoshi,Nomura, Isamu,Takanaga, Tetsuya,Sugita, Toshio,Ichikawa, Katsuhiko
, p. 810 - 814 (2007/10/02)
Ethyl dichloro(ethoxy)acetate(1) and methyl dichloro(methoxy)acetate(2) were characterized.The reaction of 1 and 2 with aromatics in the presence of AlCl3 gave a considerable yield of aromatic α-keto ester.The aromatics included mono- and polymethylbenzene and anisol.The reaction was studied under various conditions and the results were compared with the acylation by ethoxalyl or methoxalyl chloride.The reaction mechanism was also discussed.
