A General and Versatile Synthesis of 4- and 5-Oxoacids

Lhommet, G.; Freville, S.; Thuy, Vu Moc Thuy Vu Moc; Petit, H.; Celerier, J. P.

doi:10.1080/00397919608003809

Cited by 12 publications

(11 citation statements)

References 14 publications

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“…With this C ‐silylated cinnamic acid in hand, it was the major isomer derived from the benzylidene cleavage that could be used en route to the target. Specifically, alcohol 21 a 42 was esterified with 26 under Yamaguchi conditions43 to give product 27 , which was then subjected to oxidative PMB cleavage44 followed by attachment of the 4‐oxo‐8‐nonenoic acid ester segment (Scheme ) 45. In line with our expectations, treatment of the resulting diene 29 with catalytic amounts of the commercial “second‐generation” ruthenium alkylidene complex 30 46, 47 in refluxing CH 2 Cl 2 afforded macrocycle 31 as an E / Z mixture in high yield, which was hydrogenated with the aid of [RhCl(PPh 3 ) 3 ] without affecting the lateral sites of unsaturation 48.…”

Section: Resultsmentioning

confidence: 99%

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Pfisterer¹,

Eisele²,

Chen³

et al. 2011

Chemistry A European J

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Iodo- and ethynyl-containing bisalkylating bioconjugation agents 5 and 8 were achieved and allow the introduction of reactive unnatural substituents into proteins and peptides whilst the bioactive 3D structure is retained. Derivatives of the peptide hormone somatostatin bearing a single iodo or ethynyl group were prepared through intercalation into the disulfide bridge. For the first time, the exact reaction mechanism of the intercalation was elucidated by applying 2D NMR experiments and it was shown that, during the reaction, somatostatin diastereomers were formed. Site-directed modification of the ethynyl-modified peptide with a coumarin chromophore was achieved through a [1,3] dipolar Huisgen cycloaddition reaction; this suggests that such a derivative could serve as an attractive platform to prepare artificial somatostatin compound libraries. The biological activity and specificity of a representative modified somatostatin derivative was demonstrated and efficient receptor-mediated cell uptake occurred in a dose-dependent manner into receptor positive cells only. The iodo and ethynyl bioconjugation reagents presented herein could be applied for introducing such substituents into alternative peptides and proteins and, in principle, could facilitate the efficient design of a broad variety of artificial protein and peptide analogues with previously unknown bioactivities.

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Section: Resultsmentioning

confidence: 99%

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Pfisterer¹,

Eisele²,

Chen³

et al. 2011

Chemistry A European J

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“…) in the presence of a catalytic amount of CuI [7] at -20°C followed by esterification of the resulting ketocarboxylic acid with a mixture of SOCl 2 /MeOH or SOCl 2 /EtOH at -10°C to room temp. ) in the presence of a catalytic amount of CuI [7] at -20°C followed by esterification of the resulting ketocarboxylic acid with a mixture of SOCl 2 /MeOH or SOCl 2 /EtOH at -10°C to room temp.…”

Section: Preparation Of 3 From Succinic Anhydridementioning

confidence: 99%

Synthesis of gem‐Difluoromethylenated Spiro‐γ‐butyrolactones by Employing PhSCF₂Si(CH₃)₃ as a gem‐Difluoromethylenating Agent

et al. 2013

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PhSCF 2 TMS was utilized as a useful gem-difluoromethylene building block for the synthesis of gem-difluoromethylenated spiro-γ-butyrolactones. The radical cyclization of γ-alkenyl-Innovation in Chemistry, 6844 γ-gem-difluoro(phenylsulfanyl)methyl-γ-butyrolactones provided gem-difluoromethylenated spiro-γ-butyrolactones.Scheme 1. Proposed synthetic route to gem-difluoromethylenated spiro-γ-butyrolactones. 6845 nesium bromide (5 equiv.) at -10°C for 0.5 h gave the expected product 3e (27 % yield) along with 7 (53 %) after lactonization. An improved yield of 3e (52 % yield) was achieved when the reaction with the Grignard reagent was performed at -78°C for 3 h. However, a significant amount of 7 was also isolated (31 % yield). In the presence of an additive, tetrabutylammonium bromide (TBAB, 5 equiv.), homoallylmagnesium bromide reacted with 4 at -78°C for 3 h to provide 3e (62 % yield) and 7 (23 % yield). [8] Under similar reaction conditions, compounds 8a and 7 were obtained in 58 and 29 % yields, respectively, from the reaction of 4 with 1-pentenylmagnesium bromide. The formation of 7 could be rationalized by competitive reduction of the intermediate 4A owing to a β-hydrogen transfer from the Grignard reagent during the reaction. Scheme 4. Preparation of 3e and 8a from phthalic anhydride.With compounds 3e and 8a in hand, we used them to prepare the alkenyl-substituted compounds 3f-h and 8b-e in good yields through olefin cross-metathesis, as summarized in Scheme 5. Except for 8e, the alkenyl-substituted compounds were obtained as mixtures of E and Z isomers with the E isomer as the major isomer.Scheme 5. Synthesis of 3f-h and 8b-e by olefin cross-metathesis of 3e and 8a with styrene derivatives. www.eurjoc.org

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“…[10] According to the experimental con-2 1 n -C 7 reactions with succinic and glutaric anhydrides. [11] In a re- …”

Section: Introductionmentioning

confidence: 98%

Barbier-Type Reactions of Cyclic Acid Anhydrides and Keto Acids Mediated by an SmI2-(NiI2-Catalytic) System – Preparation of Disubstituted Lactones

1998

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Cyclic acid anhydrides (succinic and glutaric anhydrides and some of their derivatives) undergo fast Barbier‐type reactions mediated by samarium diiodide in the presence of catalytic amounts of nickel diiodide (1 mol‐% with respect to SmI2), to give disubstituted lactones in high yields. Without NiI2 no reaction occurs. Various alkyl and allyl iodides can be used. In these reactions the formation of a samarium keto carboxylate intermediate is likely; as a matter of fact, keto carboxylic acids react under similar conditions to also yield disubstituted lactones. It is demonstrated that lactonisation occurs during hydrolysis of the reaction.

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A General and Versatile Synthesis of 4- and 5-Oxoacids

Cited by 12 publications

References 14 publications

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Synthesis of gem‐Difluoromethylenated Spiro‐γ‐butyrolactones by Employing PhSCF₂Si(CH₃)₃ as a gem‐Difluoromethylenating Agent

Barbier-Type Reactions of Cyclic Acid Anhydrides and Keto Acids Mediated by an SmI2-(NiI2-Catalytic) System – Preparation of Disubstituted Lactones

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A General and Versatile Synthesis of 4- and 5-Oxoacids

Cited by 12 publications

References 14 publications

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Synthesis of gem‐Difluoromethylenated Spiro‐γ‐butyrolactones by Employing PhSCF2Si(CH3)3 as a gem‐Difluoromethylenating Agent

Barbier-Type Reactions of Cyclic Acid Anhydrides and Keto Acids Mediated by an SmI2-(NiI2-Catalytic) System – Preparation of Disubstituted Lactones

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Synthesis of gem‐Difluoromethylenated Spiro‐γ‐butyrolactones by Employing PhSCF₂Si(CH₃)₃ as a gem‐Difluoromethylenating Agent