32046-97-2Relevant academic research and scientific papers
A high-yielding protocol for the synthesis of 4,5-diarylpyrimidin-2-amine derivatives from chalcones
Kooramatom Unni, Krishnaraj,Menon, Prasanth K.,George, Scholly Clair,Thomas, Sajesh P.,Devaky
, p. 112 - 118 (2021/10/07)
A novel, high yielding and versatile protocol was achieved for the synthesis of 4,5-diaryl-2-pyrimidinamine derivatives from chalcones. The synthesis was accomplished by converting the chalcones into 3-chloro-2,3-diaryl-2-propen-1-ones followed by subsequent reaction with amidine derivatives.
Asymmetric epoxidation of α,β-unsaturated ketones via an amine-thiourea dual activation catalysis
Zhang, Lu-Wen,Wang, Li,Ji, Nan,Dai, Si-Yang,He, Wei
supporting information, (2021/03/15)
A simple asymmetric epoxidation method is developed to effectively synthesize chiral α-carbonyl epoxides through an amine-thiourea dual activation catalysis. In this method, TBHP, as an oxidant, determined the reaction rate, and the chiral amine-thiourea catalyst effectively controlled the stereoselectivity of the reaction, and KOH promoted deprotonation. 22 examples of α,β-unsaturated ketones with various substituent groups are smoothly converted into α-carbonyl epoxides with moderate to excellent enantiomeric excess.
Asymmetric Epoxidation of Enones Promoted by Dinuclear Magnesium Catalyst
Jaszczewska-Adamczak, Joanna A.,Mlynarski, Jacek
supporting information, p. 4247 - 4255 (2021/07/17)
Asymmetric synthesis with cheaper and non-toxic alkaline earth metal catalysts is becoming an important and sustainable alternative to conventional catalytic methodologies mostly relying on precious metals. In spite of some sustainable methods for enantioselective epoxidation of enones, the development of a well-defined and efficient catalyst based on magnesium complexes for these reactions is still a challenging task. In this perspective, we present the application of chiral dinuclear magnesium complexes for asymmetric epoxidation of a broad range of electron-deficient enones. We demonstrate that the in situ generated magnesium-ProPhenol complex affords enantioenriched oxiranes in high yields and with excellent enantioselectivities (up to 99% ee). Our extensive study verifies the literature data in this area and provides a step forward to better understand the factors controlling the oxygenation process. Elaborated catalyst offers mild reaction conditions and a truly wide substrate scope. (Figure presented.).
Asymmetric epoxidation of α,β-unsaturated ketones catalyzed by rare-earth metal amides RE[N(SiMe3)2]3with chiral TADDOL ligands
Shan, Haiwen,Lu, Chengrong,Zhao, Bei,Yao, Yingming
, p. 1043 - 1053 (2021/01/25)
The catalytic asymmetric epoxidation of α,β-unsaturated ketones by tert-butylhydroperoxide (TBHP) has been well established using rare-earth metal amides RE[N(SiMe3)2]3 (RE = La(1), Nd(2), Sm(3), Y(4), Yb(5)) with chiral TADDOL ligands. It was found that
Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones Using Amide-Based Cinchona Alkaloids as Hybrid Phase-Transfer Catalysts
Jurczak, Janusz,Majdecki, Maciej,Tyszka-Gumkowska, Agata
supporting information, (2020/11/13)
A series of 20 one chiral epoxides were obtained with excellent yields (up to 99%) and enantioselectivities (up to >99% ee) using hybrid amide-based Cinchona alkaloids. Our method is characterized by low catalyst loading (0.5 mol %) and short reaction times. Moreover, the epoxidation process can be carried out in 10 cycles, without further catalyst addition to the reaction mixture. This methodology significantly enhance the scale of the process using very low catalyst loading.
The Synthesis of Hydrobenzoin-Based Monoaza Crown Ethers and Their Application as Recyclable Enantioselective Catalysts
Nemcsok, Tamás,Rapi, Zsolt,Bagi, Péter,Oláh, Attila,Keglevich, Gy?rgy,Bakó, Péter
, p. 930 - 938 (2019/11/22)
Abstract: New recyclable monoaza-15-crown ethers have been synthesized starting from (R,R)-(+)- and (S,S)-(?)-hydrobenzoin. These macrocycles proved to be efficient and reusable phase transfer catalysts in a few asymmetric reactions under mild conditions.
Organocatalytic Enantioselective γ-Elimination: Applications in the Preparation of Chiral Peroxides and Epoxides
Chen, Zhili,Gong, Xiangnan,Hu, Fangli,Huang, Shengli,Jia, Shiqi,Qin, Wenling,Tan, Yu,Xu, Da,Yan, Hailong
, p. 1934 - 1940 (2020/03/24)
An organocatalyzed enantioselective γ-elimination process has been achieved and applied in the kinetic resolution of peroxides to access chiral peroxides and epoxides. The reaction provided a pathway for the preparation of two useful synthetic and biologically important structural motifs through a single-step reaction. A range of substrates has been resolved with a selectivity factor up to 63. The obtained enantioenriched peroxides and epoxides allowed a series of transformations with retained optical purities.
Application of chiral TADDOL ligand and rare earth metal amide in combined catalysis of asymmetric reaction
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Paragraph 0188-0191, (2020/11/23)
The invention relates to application of chiral TADDOL ligand and rare earth metal amide in combined catalysis of asymmetric epoxidation reaction of chalcone compounds. According to the application, alpha, beta-unsaturated ketone shown in a formula (1) and tert-butyl hydroperoxide react in the presence of organic alkali under the combined catalytic action of a chiral TADDOL ligand shown in a formula (3) and rare earth metal amide in an anhydrous, oxygen-free and protective atmosphere to obtain the chiral epoxy compound shown in the formula (2) after the reaction is completed, wherein R1 is selected from hydrogen, alkyl, halogen, alkoxy, trifluoromethyl, nitro or cyano, R2 is selected from phenyl, substituted phenyl, naphthyl, furyl or thienyl; R3 and R4 are respectively and independently selected from alkyl, phenyl or R3 and R4 and carbon atoms connected with R3 and R4 form naphthenic base; Ar is phenyl, substituted phenyl, biphenyl or naphthyl; the molecular formula of the rare earth metal amide is RE [N (SiMe3) 2] 3. The method has the advantages of wide substrate application range, high yield and high enantioselectivity.
Method for preparing epoxide by one-pot olefin aerobic epoxidation
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Paragraph 0048-0049, (2020/01/03)
The invention relates to a method for preparing an epoxide by one-pot olefin aerobic epoxidation, and belongs to the technical field of organic synthesis. An olefin, an alkyl aromatic compound and analkali are added into a solvent, or an olefin, an alkyl aromatic compound and an alkali are directly mixed; the temperature is raised to 70-160 DEG C in an air or oxygen atmosphere; reacting is carried out for 1-48 hours; and the olefin is directly oxidized into the corresponding epoxide in the presence of the alkyl aromatic compound, the alkali and air (or oxygen), wherein the yield is up to 99%.In the reaction process, the generated alkyl peroxide is generated in situ and consumed in situ, so that the concentration of the alkyl peroxide is kept at a lower level; and generated alkyl peroxy free radicals can also react with the olefin to further generate the peroxide, and efficiency is improved. The method has the advantages of simple operation, mild conditions, low raw material cost andno need of special complex equipment, and has a good industrial application prospect.
Method for preparing epoxide through induction of visible light
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Paragraph 0087; 0088, (2018/08/04)
The invention belongs to the technical field of organic synthesis and provides a method for preparing an epoxide through induction of visible light. The method comprises the following step: under thecondition that the visible light and a photosensitizer exist, by taking oxygen or air as an oxygen source or an oxidizing agent and taking a synthesized amidine derivative as a catalyst, performing areaction at the temperature of -40-50 DEG C for 36h-192h, so that olefin is directly oxidized into the corresponding epoxide. The method is mild in reaction conditions, and the yield is as high as 94%or above, therefore, the method has good development value and application prospect.
