97-41-6Relevant academic research and scientific papers
Asymmetric cyclopropanation method of copper-catalyzed olefin and application of asymmetric cyclopropanation method
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Paragraph 0082-0086, (2021/05/22)
The invention discloses an asymmetric cyclopropanation method of copper-catalyzed olefin and application thereof. The copper catalyst adopted by the method is generated in situ from a metal copper precursor and a chiral P, N, N-ligand in a reaction medium. The method has the characteristics of cheap catalyst, simple ligand preparation, high activity, high selectivity, mild reaction conditions, simple operation and the like, can realize continuous operation, and is suitable for large-scale industrial production. The method is also suitable for asymmetric synthesis of chiral first chrysanthemic acid which is an important intermediate of pyrethroid pesticides, the yield can reach 80%, the enantioselectivity can reach 85%, and the method can be applied to industrial preparation.
Synthesis Method of Cyclopropane or Cyclopentene Derivatives via Fe-catalyzed Cationic Radical Cycloaddition Reaction
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Paragraph 0080-0081; 0101-0102, (2021/11/02)
In this disclosure Fe (III) complex is used as an electron oxidizing agent to oxidize an electron - rich alkene compound to form a radical cation intermediate, and then a cyclopropane compound or 3 5-membered ring compound is synthesized by inducing a cycloaddition reaction with the diazo compound.
Cycloaddition Reactions of Alkene Radical Cations using Iron(III)-Phenanthroline Complex
Cho, Yong Hyun,Kim, Jae Hyung,An, Hyeju,Ahn, Kwang-Hyun,Kang, Eun Joo
supporting information, p. 2183 - 2188 (2020/04/29)
Single electron oxidation of electron-rich alkenes using the iron(III)-phenanthroline complex produced electrophilic alkene radical cations, which promoted efficient radical cation [2+1] cycloaddition reactions with diazo compounds. Subsequent chain propagation afforded tri- and tetra-substituted cyclopropanes. This methodology was also expanded to [3+2] cycloaddition reactions with vinyl diazoesters, validating this sustainable, first-row transition metal iron system for the single electron redox reactions. (Figure presented.).
Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods
Ashida, Yuichiro,Kawamoto, Momoyo,Matsuo, Noritada,Moriyama, Mizuki,Tanabe, Yoo
, p. 2984 - 2999 (2020/03/24)
Chiral total syntheses of all six insecticidal natural pyrethrins (three pyrethrin I and three pyrethrin II compounds) contained in the chrysanthemum (pyrethrum) flower were performed. Three common alcohol components [(S)-cinerolone, (S)-jasmololone, and (S)-pyrethrolone] were synthesized: (i) straightforward Sonogashira-type cross-couplings using available (S)-4-hydroxy-3-methyl-2-(2-propynyl)cyclopent-2-en-1-ones (the prallethrin alcohol) for (S)-cinerolone (overall 52% yield, 98% ee) and (S)-pyrethrolone (overall 54% yield, 98% ee) and (ii) traditional decarboxylative-aldol condensation and lipase-catalyzed optical resolution for (S)-jasmololone (overall 16% yield, 96% ee). Two counter acid segments [(1R,3R)-chrysanthemic acid (A) and (1R,3R)-second chrysanthemic acid precursor (B)] were prepared: (i) C(1) epimerization of ethyl (±)-chrysanthemates and optical resolution using (S)-naphthylethylamine to afford A (96% ee) and (ii) concise derivatization of A to B (96% ee). All six pyrethrin esters (cinerin I/II, jasmolin I/II, and pyrethrin I/II) were successfully synthesized utilizing an accessible esterification reagent (TsCl/N-methylimidazole). To investigate the stereostructure-activity relationship, all four chiral stereoisomers of cinerin I were synthesized. Three alternative syntheses of (±)-jasmololone were investigated (methods utilizing Piancatelli rearrangement, furan transformation, and 1-nitropropene transformation). Insecticidal activity assay (KD50 and IC50) against the common mosquito (Culex pipiens pallens) revealed that (i) pyrethrin I > pyrethrin II, (ii) pyrethrin I (II) > cinerin I (II) ? jasmolin I (II), and (iii) "natural" cinerin I ? three "unnatural" cinerin I compounds (apparent chiral discrimination).
High-yield ethyl chrysanthemate preparation method
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Paragraph 0037-0080, (2020/12/08)
The invention belongs to the technical field of chemical processes, and specifically relates to a high-yield ethyl chrysanthemate preparation method. The high-yield ethyl chrysanthemate preparation method comprises the following steps: (1) diazotization: a step of adding water, glycine ethyl ester acid salt, glacial acetic acid and dimethyl carbonate as solvents into a diazotization kettle, dropwisely adding a sodium nitrite aqueous solution into the diazotization kettle, and carrying out a reaction so as to a diazo liquid; (2) cyclization: a step of putting 2,5-dimethyl-2,4-hexadiene into a cyclization kettle, and carrying out a reaction with cuprous chloride as a catalyst so as to obtain a cyclized solution; (3) desolventizing: a step of sending the cyclized solution into a high-yield desolventizing tower to remove the solvents so as to obtain a crude ethyl chrysanthemate product; and (4) distillation: a step of putting the crude ethyl chrysanthemate product into a distillation kettle, and carrying out vacuum distillation so as to obtain the high-purity ethyl chrysanthemate. The high-yield ethyl chrysanthemate preparation method provided by the invention has the following beneficial effects: when the dimethyl carbonate is used as a solvent, a diazotization reaction can be carried out more completely, so the loss of raw materials is reduced; and meanwhile, the yield of ethyl chrysanthemate in the subsequent cyclization reaction can be improved.
Bottom-Up Synthesis of Acrylic and Styrylic RhII Carboxylate Polymer Beads: Solid-Supported Analogs of Rh2(OAc)4
Levchenko, Vladimir,Sundsli, B?rd,?ien-?degaard, Sigurd,Tilset, Mats,Hansen, Finn K.,Bonge-Hansen, Tore
supporting information, p. 6150 - 6157 (2018/11/23)
We have developed a short and efficient bottom-up synthesis of acrylic and styrylic polymer beads containing dirhodium(II) tetracarboxylates. The solid supported dirhodium(II) tetracarboxylate catalysts were synthesized in as little as two steps overall from dirhodium tetratrifluoroacetate and commercially available carboxylic acids, making the bottom-up approach a viable alternative to the post-modification approach commonly used. The dirhodium(II) tetracarboxylate polymer beads have a convenient size (ca. 100 μm), are easy to handle, and can be considered solid-supported analogs of Rh2(OAc)4. Beads generated from dirhodium(II) tetracarboxylates with four polymerizable carboxylate ligands displayed the best catalytic performance and compared favorably to Rh2(OAc)4 in benchmarked cyclopropanation reactions. The results imply that the cumbersome synthesis of monomeric dirhodium(II) tetracarboxylates with mixed ligands systems can be avoided and that immobilized dirhodium(II)-catalysts with a higher degree of crosslinking is a viable option to catalysts linked in an anchor-like fashion. We demonstrate recovery and recycling, and a potential use of the beads as catalysts in a cyclopropanation reaction towards the insecticide chrysanthemic acid.
Cobalt-Catalyzed Reductive Dimethylcyclopropanation of 1,3-Dienes
Werth, Jacob,Uyeda, Christopher
supporting information, p. 13902 - 13906 (2018/10/02)
Dimethylcyclopropanes are valuable synthetic targets that are challenging to access in high yield using Zn carbenoid reagents. Herein, we describe a cobalt-catalyzed variant of the Simmons–Smith reaction that enables the efficient dimethylcyclopropanation of 1,3-dienes using a Me2CCl2/Zn reagent mixture. The reactions proceed with high regioselectivity based on the substitution pattern of the 1,3-diene. The products are vinylcyclopropanes, which serve as substrates for transition-metal-catalyzed ring-opening reactions, including 1,3-rearrangement and [5+2] cycloaddition. Preliminary studies indicate that moderately activated monoalkenes are also amenable to dimethylcyclopropanation under the conditions of cobalt catalysis.
Preparing method of cis, trans-ethyl 2, 2-dimethyl-3-(1-isobutenyl)cyclopropane-1-carboxylate
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Paragraph 0014; 0015; 0016, (2017/08/27)
The invention discloses a method of preparing cis, trans-ethyl 2,2-dimethyl-3-(1-isobutenyl)cyclopropane-1-carboxylate, comprising of making the ethyl glycinate hydro and sodium nitrite in the solvent diazo-react without additional addition of organic acid or mineral acid to get ethyl diazoacetate which is to react with the 2,5-Dimethyl-2,4-hexadiene under the catalyst effect and then be desolvated and rectificated to get ethyl chrysanthemumate.The invention is easy to use with high production yield and high contents.
Cu and Au metal-organic frameworks bridge the gap between homogeneous and heterogeneous catalysts for alkene cyclopropanation reactions
Corma, Avelino,Iglesias, Marta,Llabres i Xamena, Francesc X.,Sanchez, Felix
experimental part, p. 9789 - 9795 (2010/11/02)
The copper and gold metal-organic frameworks (MOFs) [Cu3(BTC) 2(H2O)3]n, [Cu3(BTC) 2] (BTC = benzene-1,3,5-tricarboxylate), and IRMOF-3-SI-Au are active and reusable solid catalysts for the cyclopropanation of alkenes with high chemo- and diastereoselectivities. This type of material gives better results than previous solid catalysts while working together with the homogeneous catalysts. These MOFs can help to bridge the gap between homogeneous and heterogeneous catalysis.
Polyoxometalates: Powerful catalysts for atom-efficient cyclopropanations
Boldini, Irene,Guillemot, Geoffroy,Caselli, Alessandro,Proust, Anna,Gallo, Emma
supporting information; experimental part, p. 2365 - 2370 (2010/12/25)
The polyoxometalate-based catalytic cyclopropanation of olefins by ethyl diazoacetate (EDA) is reported. The outstanding catalyst productivity (TONs up to 100,000) and the use of equimolar EDA/olefin ratio confer to the methodology a high sustainability. Preliminary mechanistic investigations are also discussed.
