The First Practical Synthesis of (<i>S</i>)-Pyrethrolone, an Alcohol Moiety of Natural Pyrethrins I and II

Matsuo, Nobutake; Takagaki, Tohei; Watanabe, Keisuke; Ohno, Nobuo

doi:10.1271/bbb.57.693

Cited by 6 publications

(5 citation statements)

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“…( S )-Prallethrin alcohol ( 1 ) was subjected to a Sonogashira-type direct vinylation-cross-coupling reaction with vinyl bromide using Pd(Ph 3 ) 4 /CuI/Et 3 N catalysis to afford ene-yne alcohol 6 in 70% yield. Z -Stereocontrolled Zn-mediated partial reduction of the triple bond in 6 furnished ( S )-pyrethrolone ( 7 ) in 77% yield (98% ee). Esterification between 7 and (1 R ,3 R )-chrysanthemic acid ( 9 ) produced pyrethrin I in a yield of 74%.…”

Section: Resultsmentioning

confidence: 99%

Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods

et al. 2020

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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).

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Section: Resultsmentioning

confidence: 99%

Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods

et al. 2020

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“…Production of the final carbon scaffold could be readily achieved by implementing similar Sonogashira cross-coupling conditions to those used by Matsuo and co-workers. 5,7 Prior to addition of the catalytic components, a solution of vinyl bromide in THF was deaereated with argon to prevent the competitive Glaser coupling of the alkynyl substrate 7. The enyne 8 was generated by reaction with the vinyl bromide in the presence of Pd(Ph3P)4, CuI and Et3N.…”

Section: Author(s)mentioning

confidence: 99%

“…(Z)-Pyrethrolone was readily identified by NMR analysis with the spectroscopic data in agreement with previously reported data. 5,7 Specifically, the H-8' (5.33 ppm) and H-9' (6.01 ppm) proton resonances of the newly formed double bond acted as diagnostic signals for the identification of (Z)pyrethrolone 9 with their correlations to H-7' and H-10', respectively, serving to confirm the regiochemistry of the side chain. Additionally, the JH-H between these two double bond resonances being of comparable magnitude to typical cisoid coupling constants confirmed the desired (Z)-configuration was achieved.…”

Section: Author(s)mentioning

confidence: 99%

“…The solvent was removed in vacuo and the resulting viscous liquid was distilled under vacuum (150 C at 0.8 mmHg) giving 7 as a yellow oil (1.47 g, 72%). 1 H NMR (600 MHz, CDCl3) δ 4.74 (1H, brd, J 6.1 Hz), 3.08-3.15 (2H, m), 2.80 (1H, dd, J 18.4, 6.1 Hz), 2.30 (1H, dd, J 18.4, 1.9 Hz), 2.22 (3H, s), 1.96 (1H, t, J 2.7 Hz); 13 7 A solution of 4-hydroxy-3-methyl-2-(2propyn-1-yl)-2-cyclopenten-1-one (7) (741 mg, 4.94 mmol) and triethylamine (2.5 mL, 18 mmol) in 1.0 M in THF vinyl bromide solution (12 mL, 12 mmol) was deaereated with argon over 40 min. Under an atmosphere of argon, tetrakis(triphenylphosphine)palladium(0) (252 mg, 0.218 mmol, 5 mol %) and copper(I) iodide (94 mg, 0.49 mmol, 10 mol %) were added with stirring.…”

Section: -Hydroxy-3-methyl-2-(2-propyn-1-yl)-2-cyclopenten-1-one (7)mentioning

confidence: 99%

“…Notably, an intermediate chiral resolution was undertaken to afford the natural (S)-enantiomer (Scheme 1). 6,7 However, this pathway suffers from the drawback of relying on regioselective reaction with intermediates containing multiple sites of reactivity, specifically the alkylation of dimethyl-3-oxoglutarate (4) and the subsequent decarboxylative aldol addition, giving the critical linear intermediate 6.…”

Section: Introductionmentioning

confidence: 99%

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A modified synthesis of (Z)-pyrethrolone

Johnston¹,

Markham²,

Duggan³

2022

Arkivoc

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An accessible, efficient, and reliable synthesis for the production of (Z)-pyrethrolone remains necessary as previous syntheses suffer from drawbacks including the use of toxic reagents, expensive starting materials and lack of regioselectivity in the production of key intermediates. This work attempts to alleviate the issues of prior syntheses by making use of well-known and regioselective transformations for the efficient synthesis of (Z)-pyrethrolone. Ultimately, (Z)-pyrethrolone is generated in an overall 20% yield over five steps from a cheap, easily accessible starting material using reliable, optimised transformations.

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Pyrethroids

Pap¹

2002

Encyclopedia of Agrochemicals

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The insecticidal synthetic pyrethroids are chemical analogs of the natural pyrethrins occurring in the flower of the Chrysanthemum cinerariaefolium plant. They represent an extensively developed insecticide group with 40 established compounds. Of the 40 commercialized active ingredients, 37 are esters. The application rate of the most potent agricultural pyrethroids is very low, ranging between 5 and 20 g/ha, representing an acceptable environmental load. Pyrethroids are also regarded as safe compounds to warm‐blooded animals and generally to the environment; however, they have some adverse effects on mites, beneficial insects, and aquatic organisms. Pyrethroids are contact nerve poisons acting on gating kinetics of sodium channel in nerve membrane. This action is highly stereoselective. Due to this specific action and their extensive use, the risk of resistance development is relatively high in the targeted insect pest populations. Consequently, resistance management strategies are urgently needed to sustain their appropriate field performance. The registered tendencies of pyrethroid usage and the recent trends in R&D both suggest that this particular group of compounds has been playing an integrated part in present pest management as it is described in our comprehensive survey. Natural Pyrethrin PyrethrinI as the Lead Structure of the Synthetic Pyrethroids Stereochemistry How to Define Pyrethroids Nomenclature Physicochemical Properties Agricultural Use Chemistry Biological Activity, Mode of Action, Metabolism

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The First Practical Synthesis of (S)-Pyrethrolone, an Alcohol Moiety of Natural Pyrethrins I and II

Cited by 6 publications

References 3 publications

Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods

Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods

A modified synthesis of (Z)-pyrethrolone

Pyrethroids

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