Synthesis of Secondary Enamides by Ruthenium‐Catalyzed Selective Addition of Amides to Terminal Alkynes

Gooßen, Lukas J.; Salih, Kifah S. M.; Blanchot, Mathieu

doi:10.1002/anie.200803068

Cited by 88 publications

(29 citation statements)

References 51 publications

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“…Notably, the E / Z mixtures of N ‐acetyl enamides 4 j – l formed in the reactions of (2‐azidoethyl)benzene derivatives were converted quantitatively into the E isomers by heating the mixtures at 110 °C for 24 h (Scheme ) . It is also notable that E isomers 4 o – q were formed exclusively by the use of benzoic anhydride instead of acetic anhydride under the conditions of Table .…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Enamides by Ruthenium‐Catalyzed Reaction of Alkyl Azides with Acid Anhydrides in Ionic Liquid

et al. 2015

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Enamides were synthesized by a ruthenium‐catalyzed one‐pot, one‐step procedure from alkyl azides and acid anhydrides. The substrate scope includes not only secondary azides, but also primary aliphatic ones to give a wide range of enamides containing various functional groups. This one‐step procedure was based on the newly discovered activity of Severin's diruthenium complex ([Cp^RuCl2]2: Cp^=η5‐1‐methoxy‐2,4‐di‐tert‐butyl‐3‐neopentylcyclopentadienyl) for the transformation of alkyl azides into the corresponding N−H imine intermediates in ionic liquids. The formation of ruthenium tetrazene complexes was observed in the stoichiometric reaction of Severin's complex with alkyl azides, which acted as the catalyst for the formation of N−H imine intermediates.

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Section: Methodsmentioning

confidence: 99%

Synthesis of Enamides by Ruthenium‐Catalyzed Reaction of Alkyl Azides with Acid Anhydrides in Ionic Liquid

et al. 2015

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“…To validate the expected chemical shifts from an ␣␤-unsaturated MftA*, the model compound L-Val-p-(2-aminoethenyl) phenol was synthesized following modifications of previously reported synthetic routes (supplemental Schemes S1 and S2) (20,21). We synthesized both cis and trans model compounds because the isomeric form of the peptide product had yet to be identified.…”

Section: Nmr and 1 H Nmr Of Mfta* Suggested That An Unsaturated Carmentioning

confidence: 99%

Mechanistic elucidation of the mycofactocin-biosynthetic radical S-adenosylmethionine protein, MftC

Khaliullin

Ayikpoe

Tuttle

et al. 2017

Journal of Biological Chemistry

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Ribosomally synthesized and posttranslationally modified peptide (RiPP) pathways produce a diverse array of natural products. A subset of these pathways depends on radical -adenosylmethionine proteins to modify the RiPP-produced peptide. Mycofactocin biosynthesis is one example of an-adenosylmethionine protein-dependent RiPP pathway. Recently, it has been shown that MftC catalyzes the oxidative decarboxylation of the C-terminal tyrosine (Tyr-30) on the mycofactocin precursor peptide MftA; however, this product has not been verified by techniques other than MS. Herein, we provide a more detailed study of MftC catalysis and report a revised mechanism for MftC chemistry. We show that MftC catalyzes the formation of two isomeric products. Using a combination of MS, isotope labeling, and H andC NMR techniques, we established that the major product, MftA*, is a tyramine-valine-cross-linked peptide formed by MftC through two -adenosylmethionine-dependent turnovers. In addition, we show that the hydroxyl group on MftA Tyr-30 is required for MftC catalysis. Furthermore, we show that a substitution in the penultimate MftA Val-29 position causes the accumulation of an MftA** minor product. TheH NMR spectrum indicates that this minor product contains an αβ-unsaturated bond that likely arises from an aborted intermediate of MftA* synthesis. The finding that MftA* is the major product formed during MftC catalysis could have implications for the further elucidation of mycofactocin biosynthesis.

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“…The residue was taken in CH 2 Cl 2 (20 mL) and washed with 10% aqueous Na 2 CO 3 solution (3 mL), water (3 mL), brine (3 mL), dried over Na 2 SO 4 and concentrated. The residue was purified by silica gel column chromatography (1À4% EtOAc/hexane) to give 28 To a solution of compound 28 (856 mg, 2.0 mmol) in anhydrous THF (10 mL) were added prolinamide 25 (128 mg, 1.0 mmol), Pd(OAc) 2 (22.5 mg, 0.1 mmol) and K 3 PO 4 (637 mg, 3.0 mmol). Resultant reaction solution was stirred at 70À80 C for 13 h. After that reaction solution was cooled up to room temperature and filtered through a small silica gel pad and eluted with CH 2 Cl 2 .…”

Section: Synthesis Of Enamidementioning

confidence: 99%

Synthesis of marine brominated alkaloid amathamide F: a palladium-catalyzed enamide synthesis

2015

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a b s t r a c tSynthesis of brominated marine natural product amathamide F is described. Various strategies to construct the enamide functionality required for its synthesis have been explored. Finally, we succeeded in constructing the enamide moiety under a palladium-catalyzed condition. Facile transformation of 2,3,4-tribromo-5-methoxybenzaldehyde to the reported structure of amathamide F involved initial onecarbon-elongation of the aldehyde group followed by its conversion to corresponding enol acetate derivative prior to crucial Pd(II)-catalyzed cross-coupling with (S)-1-methylpyrrolidine-2-carboxamide. However, due to nonconformity of its NMR spectral data to that of the reported natural isolate, we have confirmed its actual structure through a synthesis.

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Synthesis of Secondary Enamides by Ruthenium‐Catalyzed Selective Addition of Amides to Terminal Alkynes

Cited by 88 publications

References 51 publications

Synthesis of Enamides by Ruthenium‐Catalyzed Reaction of Alkyl Azides with Acid Anhydrides in Ionic Liquid

Synthesis of Enamides by Ruthenium‐Catalyzed Reaction of Alkyl Azides with Acid Anhydrides in Ionic Liquid

Mechanistic elucidation of the mycofactocin-biosynthetic radical S-adenosylmethionine protein, MftC

Synthesis of marine brominated alkaloid amathamide F: a palladium-catalyzed enamide synthesis

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