97-41-6Relevant articles and documents
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.
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).