Chemical and microsomal oxidation of tertiary amides: regio- and stereoselective aspects

Iley, Jim; Tolando, Roberto; Constantino, Luís

doi:10.1039/b102731j

Cited by 12 publications

(14 citation statements)

References 31 publications

(22 reference statements)

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“…However, under certain conditions, tertiary amides undergo α-hydroxylation followed by oxidative dealkylation to yield secondary amides and aldehydes. 8 In addition, when no α-hydrogen is available an alternative route could take place, for example, sidechain N-methoxylation: 9 The present work describes the synthesis of amides of type Ph 2 CHCONHAr (Scheme 1) (lacking hydrogen(s) at the α position to N), and their anodic oxidation in acetonitrile under controlled potential electrolysis (CPE). The outcome from their preparative electrolysis indicates that they undergo various types Scheme 1 Synthesized substituted amides for electrolysis.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical oxidation of amides of type Ph2CHCONHAr

Golub

Becker

2012

Org. Biomol. Chem.

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Anodic oxidation of N-aryl-2,2-diphenylacetamides in acetonitrile undergoes three types of bond-cleavage, one between the benzylic carbon and the carbonyl group, the second between a carbonyl and 'N', and the third between the 'N' atom and aryl group. The selectivity of the cleavage and nature of emerged products is highly dependent on the nature of substituent attached to the aryl group. For example, electron-withdrawing groups direct the benzyl-carbonyl bond-breaking whereas electron-donating substituents favor the N-aryl bond cleavage. The type of products obtained involve benzophenone, 2,2-diphenylacetamide, N-(diphenylmethylene)acetamide, N-(diphenylmethyl)acetamide, α-lactam (1-acetyl-3,3-diphenylaziridin-2-one, as a 1 : 1 complex with 2,4-dinitroaniline) and aniline derivatives.

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Section: Introductionmentioning

confidence: 99%

Electrochemical oxidation of amides of type Ph2CHCONHAr

Golub

Becker

2012

Org. Biomol. Chem.

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“…43 The operation of stereoelectronic effects has been proposed in order to account for the peculiar inter-and intramolecular selectivities observed in HAT reactions from amides and lactams to a variety of hydrogen-abstracting species. For example, in product studies of the reactions of 1-methyl-2-pyrrolidone and other lactams with the tert-butoxyl radical, 44 the ethyl radical, 45 and photoexcited tetrabutylammonium decatungstate, 46 preferential formation of products derived from HAT from the ring C−H bonds adjacent to nitrogen (Scheme 2, a) as compared to the exocyclic methyl C−H bonds (Scheme 2, b) was observed, as quantified by the product ratios derived from the two competitive pathways that are between 6 and 13.…”

Section: ■ Introductionmentioning

confidence: 99%

Absolute Rate Constants for Hydrogen Atom Transfer from Tertiary Amides to the Cumyloxyl Radical: Evaluating the Role of Stereoelectronic Effects

et al. 2014

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Absolute rate constants for hydrogen atom transfer from tertiary amides to the cumyloxyl radical: evaluating the role of stereoelectronic effects Salamone, Michela; Milan, Michela; Dilabio, Gino A.; Bietti, Massimo http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=fr L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21272696&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21272696&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1021/jo5013459Journal of Organic Chemistry, 79, 15, pp. 7179-7184, 2014-07-10 Absolute ABSTRACT: A time-resolved kinetic study of the hydrogen atom transfer (HAT) reactions from a series of alkanamides to the cumyloxyl radical (CumO •) was carried out. With N,N-dialkylformamides HAT preferentially occurs from the formyl C−H bond, while in N-formylpyrrolidine HAT mostly occurs from the ring α-C−H bonds. With the acetamides and the alkanamides almost exclusive HAT from the C−H bonds that are α to nitrogen was observed. The results obtained show that alignment between the C−H bond being broken and the amide π-system can lead to significant increases in the HAT rate constant (k H ). This finding points toward the important role of stereoelectronic effects on the HAT reactivity and selectivity. The highest k H values were measured for the reactions of CumO• with N-acylpyrrolidines. These substrates have ring α-C−H bonds that are held in a conformation that is optimally aligned with the amide π-system, thus allowing for the relatively facile HAT reaction. The lowe...

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“…An at least one order of magnitude increase in reactivity ( k rel ≥ 10) was observed following N-methylation as in S20 , indicating that HAT now selectively occurs from the N -methyl group, in line with the results of previous studies on the radical-based oxidation of this substrate. 24 However, the relatively low k H value reflects the divergent contribution of deactivating electronic effects and hyperconjugative activation. Significantly higher k H values were measured for the other six derivatives displayed in Table 3 , with k rel values that were observed to progressively increase going from the 2-oxazolidinone to the 2-pyrrolidone and 2-imidazolidinone substrate groups, ranging between 89 for 2-oxazolidinone ( S17 ) and 3220 for 1,3-dimethyl-2-imidazolidinone ( S15 ).…”

Section: Results and Discussionmentioning

confidence: 99%

Factors Governing Reactivity and Selectivity in Hydrogen Atom Transfer from C(sp³)–H Bonds of Nitrogen-Containing Heterocycles to the Cumyloxyl Radical

et al. 2022

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A kinetic study of the hydrogen atom transfer (HAT) reactions from nitrogen-containing heterocycles (secondary and tertiary lactams, 2-imidazolidinones, 2-oxazolidinones, and succinimides) to the cumyloxyl radical has been carried out employing laser flash photolysis with ns time resolution. HAT occurs from the C–H bonds that are α to nitrogen, activated by hyperconjugative overlap with the N–C=O π system. In the lactam series, the second-order HAT rate constant ( k H ) was observed to decrease by a factor of ∼4 going from the five- and six-membered ring derivatives to the eight-membered ones, a behavior that was rationalized on the basis of a reduced extent of hyperconjugative activation associated to the greater flexibility of the larger rings compared to the smaller ones. In the five-membered-ring substrate series, the k H values were observed to increase by >3 orders of magnitude on going from succinimide to 2-imidazolidinones, a behavior that was explained in terms of the divergent contribution of hyperconjugative activation and deactivating electronic effects determined by ring functionalities. The results are discussed in the framework of the development of HAT-based C–H bond functionalization procedures.

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Chemical and microsomal oxidation of tertiary amides: regio- and stereoselective aspects

Cited by 12 publications

References 31 publications

Electrochemical oxidation of amides of type Ph2CHCONHAr

Electrochemical oxidation of amides of type Ph2CHCONHAr

Absolute Rate Constants for Hydrogen Atom Transfer from Tertiary Amides to the Cumyloxyl Radical: Evaluating the Role of Stereoelectronic Effects

Factors Governing Reactivity and Selectivity in Hydrogen Atom Transfer from C(sp³)–H Bonds of Nitrogen-Containing Heterocycles to the Cumyloxyl Radical

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Chemical and microsomal oxidation of tertiary amides: regio- and stereoselective aspects

Cited by 12 publications

References 31 publications

Electrochemical oxidation of amides of type Ph2CHCONHAr

Electrochemical oxidation of amides of type Ph2CHCONHAr

Absolute Rate Constants for Hydrogen Atom Transfer from Tertiary Amides to the Cumyloxyl Radical: Evaluating the Role of Stereoelectronic Effects

Factors Governing Reactivity and Selectivity in Hydrogen Atom Transfer from C(sp3)–H Bonds of Nitrogen-Containing Heterocycles to the Cumyloxyl Radical

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Factors Governing Reactivity and Selectivity in Hydrogen Atom Transfer from C(sp³)–H Bonds of Nitrogen-Containing Heterocycles to the Cumyloxyl Radical