- Oxiranyl remote anions from epoxy cinnamates and their application towards the synthesis of α,β-epoxy-γ-butyrolactones
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A series of α,β-epoxy-γ-butyrolactones were synthesized in moderate yields via oxiranyl remote anions derived from epoxy cinnamate esters. The key synthetic step involved deprotonation of the β-position of α,β-epoxy cinnamate derivatives where the generated β-anion was stabilized by remote chelation from an ester group. The substitution reaction of the anion with a variety of ketones, followed by cyclization, readily furnished the desired substituted α,β-epoxy-γ-butyrolactones.
- Sermmai, Patpanat,Ruangsupapichat, Nopporn,Thongpanchang, Tienthong
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supporting information
(2020/11/19)
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- Development of a robust and practical process for the Darzens condensation and α,β-epoxide rearrangement: Scope and limitations of the methodology
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A practical and robust process for the Darzens condensation of substituted benzaldehydes and subsequent α,β-epoxy rearrangement is reported. The process developed is both amenable to large scale and parallel synthesis. While electron-poor benzaldehydes gave mixtures of aryl ketones and 2-substituted aryl ketones in mediocre to low yields, electron-rich benzaldehydes were found to react in high yields with complete regioselectivity to form 2-substituted aryl ketones. Georg Thieme Verlag Stuttgart.
- Zimbron, Jeremy Malcolm,Seeger-Weibel, Manuela,Hirt, Hans,Gallou, Fabrice
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p. 1221 - 1226
(2008/12/22)
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- Ligand exchange reaction of sulfoxides in organic synthesis: A novel method for generation of magnesium enolates and its application to synthesis of α-halocarboxylic acid derivatives and α-haloaldehydes
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A new method for synthesis of α-halo(Cl, F)carboxylic acid derivatives and α-haloaldehydes is described. α-Halo-α-sulfinyl carboxylic acid, esters, and α-halo-α-sulfinyl aldehydes were easily prepared from aryl 1-haloalkyl sulfoxides and alkyl chloroformate and ethyl formate, respectively, in good yields. α-Chloro-α-sulfinyl amides were synthesized from (p-tolylthio)acetic acid. Ligand exchange reaction of the sulfinyl group of these acids, esters, amides, and aldehydes with ethylmagnesium bromide gave the magnesium enolates, which were treated with water to give α-halocarboxylic acid derivatives and α-chloroaldehydes in good yields. The magnesium enolates derived from the α-chloro-α-sulfinyl acid derivatives were trapped with carbonyl compounds to afford the adducts, which were transformed to α,β-epoxy carboxylic acid derivatives. Thermal elimination of the sulfinyl group in the α-halo-α-sulfinyl acid derivatives and the α-halo-sulfinyl aldehydes gave α-halo-α,β-unsaturated carboxylic acid derivatives and α-halo-α,β-unsaturated aldehydes in high yields.
- Satoh,Kitoh,Onda,Takano,Yamakawa
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p. 4957 - 4972
(2007/10/02)
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- MASS SPECTROMETRIC DECOMPOSITION OF β-PHENYLOXIRANECARBOXYLIC ESTERS
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The electron-impact mass spectra of the E- and Z-isomers of the α,β-methyl substituted esters of β-phenyloxiranecarboxylic acids have been studied.
- Anisimova, O. S.,Chistyakov, V. V.,Bokanov, A. I.,Shvedov, V. I.,Sheinker, Yu. N.
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p. 1058 - 1063
(2007/10/02)
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- Dianions Derived from α-Halo Acids. The Darzens Condensation Revisited
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The dianions of α-halo carboxylic acids are readily generated by the addition of the acids to 2 equiv of lithium diisopropylamide at low temperatures.When the mixture warms to room temperature dimeric products are formed.When aldehydes and ketones were added to the cooled solutions of the dianions and the reaction mixtures were allowed to warm to room temperature, followed by acid quench, glycidic acids were formed.The glycidic acids, per se, were often too unstable to be isolated and purified but could be analyzed by conversion to their methyl esters withdiazomethane.When the reactions were quenched prematurely, α-chloro-β-hydroxy carboxylic acids were isolated.Homologated aldehydes and ketones were obtained from the glycidic acids by catalytic and thermal decarboxylation methods.
- Johnson, Carl R.,Bade, Thomas R.
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p. 1205 - 1212
(2007/10/02)
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- NEW SYNTHETIC ROUTES TO β-FLUORO β-PHENYLLACTIC ACID DERIVATIVES AND Β-FLUOROCYANOHYDRINS
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Alkyl phenyl 2,3-epoxycarboxylates from the well-known Darzens glycidic esters synthesis react under very mild conditions with pyridinium-poly-hydrogen fluoride to give corresponding 3-fluoro 3-phenyllactates in almost quantitative yields with a high regio and stereoselectivity.This method can be applied succesfully to other flycidic derivatives: glycidoamides, glycidonitriles, glycidoiminoesters...The spectrometric properties (IR, NMR) are presented.
- Ayi, A. I.,Remli, M.,Condom, R.,Guedj, R.
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p. 565 - 580
(2007/10/02)
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