41641-25-2Relevant 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).
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.
Synthesis and characterisation of new polynuclear copper(I) pyrazolate complexes and their catalytic activity in the cyclopropanation of olefins
Maspero, Angelo,Brenna, Stefano,Galli, Simona,Penoni, Andrea
, p. 123 - 129 (2007/10/03)
The reaction of [Cu(CH3CN)4](BF4) with racemic pyrazole-3,5-dicarboxylic acid di-sec-butyl ester (3,5-dicarbo-sec-butoxypyrazole, Hdcsbpz) or with pyrazole-3,5-di-ter-butyl (3,5-di-ter-butylpyrazole, Hdtbpz) quantitatively yields the new [Cu(dcsbpz)]4 and [Cu(dtbpz)]4 complexes, respectively. Crystals of [Cu(dcsbpz)]4 are triclinic, P1?, a =10.9748(7), b =11.8399(8), c =26.5575(17) ?, α =100.605(2), β =90.783(2), γ =105.362(2)°; [Cu(dtbpz)]4·CH2Cl2 is monoclinic, P21/n, a =10.902(3), b =19.200(3), c =25.772(4) ?, β =93.86(2)°. Both species contain cyclic tetrameric molecules, with the heterocyclic ligands binding in the common N,N′-exo-bidentate mode; however, the shape and geometry of the inner Cu4 moiety is remarkably different, as highlighted, for example, by the absolute values of the 1,2 and 1,3 (non-bonding) Cu?Cu interactions. These polynuclear copper(I) pyrazolate complexes catalyse the conversion of alkenes into the corresponding cyclopropane derivatives with interesting diastereomeric excesses. Aiming at the evaluation of their catalytic activities, a systematic study of the cyclopropanation reactions in the presence of ethyl diazoacetate has been performed.
Copper(I)-homoscorpionate catalysts for the preferential, kinetically controlled cis cyclopropanation of α-olefins with ethyl diazoacetate
Diaz-Requejo, M. Mar,Caballero, Ana,Belderrain, Tomas R.,Nicasio, M. Carmen,Trofimenko, Swiatoslaw,Perez, Pedro J.
, p. 978 - 983 (2007/10/03)
In situ prepared copper catalysts TpxCu (Tpx = homoscorpionate) catalyze the olefin cyclopropanation reaction using ethyl diazoacetate as the carbene source. Very high values of both activity and diastereoselectivity toward the cis isomer have been obtained for styrene, α-methylstyrene, 1-hexene, 1-octene, vinyl acetate, n-butyl vinyl ether, 2,5-dimethyl-2,4-hexadiene, and 3,3-dimethyl-1-butene. The effect of the temperature in the diastereoselectivity was almost negligible within the range -10 to +30°C. Kinetic studies have allowed us to propose that the homoscorpionate ligand might act in a dihapto form during the catalytic process. This transformation seems to operate under kinetic control, where the formation of the cis isomer would govern the reaction rate.
