Versatile and Direct Transformation of Secondary Amides into Ketones by Deaminative Alkylation with Organocerium Reagents

Xiao, Kai‐Jiong; Wang, Ai‐E; Huang, Yong; Huang, Pei‐Qiang

doi:10.1002/ajoc.201200066

Cited by 75 publications

(8 citation statements)

References 36 publications

(13 reference statements)

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“…Considering the low efficiency of the classical amide activators such as P 2 O 5 and POCl 3 3 4 10 , highly electrophilic trifluoromethanesulfonic (triflic) anhydride (Tf 2 O) 28 was selected for our purpose. Tf 2 O in combination with a base such as 2,6-di- tert -butyl-4-methylpyridine (DTBMP) 29 , Hünig base 30 , 2-chloropyridine 31 , 2-fluoropyridine 32 33 34 35 36 , 2-iodopyridine 37 , 2,4,6-collidine 38 39 40 41 , and 3-cyanopyridine 42 had been employed for the activation of amides in various C–C bond-forming reactions. A secondary amide 1 , once treated with Tf 2 O, would generate a highly reactive nitrilium intermediate A 32 34 35 36 43 ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Metal-Free C–H Alkyliminylation and Acylation of Alkenes with Secondary Amides

Huang

Geng

et al. 2016

Sci Rep

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Carbon–carbon bond formation by metal-free cross-coupling of two reactants with low reactivity represents a challenge in organic synthesis. Secondary amides and alkenes are two classes of bench-stable compounds. The low electrophilicity of the former and low nucleophilicity of the latter make the direct coupling of these two partners challenging yet highly desirable. We report herein an unprecedented intermolecular reaction of secondary amides with alkenes to afford α,β-unsaturated ketimines or enones, which are versatile intermediates for organic synthesis and are prevalent in bioactive compounds and functional materials. Our strategy relies on the chemoselective activation of the secondary amide with trifluoromethanesulfonic anhydride (Tf2O)/2-fluoropyridine to generate a highly reactive nitrilium intermediate, which reacts efficiently with alkenes. This metal-free synthesis is characterized by its mild reaction conditions, excellent functional group tolerance and chemoselectivity, allowing the preparation of multi-functionalized compounds without using protecting groups.

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Section: Resultsmentioning

confidence: 99%

Metal-Free C–H Alkyliminylation and Acylation of Alkenes with Secondary Amides

Huang

Geng

et al. 2016

Sci Rep

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“…Notable achievements include the use of secondary amides as precursors, pioneered by Huang. 36 Using CrCl 3 and TMSCl, we found that low-valent Cr formed in situ promotes the coupling of secondary amides with aryl Grignard, providing access to diarylated ketones upon workup (Scheme 8d). 37 The ketones are protected in the catalysis, thereby preventing the formation of the adducts of Grignard reagents to ketones.…”

Section: Bonds By Crmentioning

confidence: 99%

Mechanistic Diversity of Low-Valent Chromium Catalysis: Cross-Coupling and Hydrofunctionalization

2021

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“…To our knowledge, this course of reaction was unprecedented. Until now, the synthesis of ketones from secondary amides and organolithium reagents required prior activation of amide with triflic anhydride [35] and in situ generation of organocerium species (addition of CeCl 3 ) [36].…”

Section: Synthesis Of 3-9mentioning

confidence: 99%

Electrophile-Dependent Reactivity of Lithiated N-Benzylpyrene-1-Carboxamide

et al. 2022

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In this paper, we describe the lithiation of N-benzylpyrene-1-carboxamide with RLi-TMEDA. We found that the reaction outcome strongly depends on the electrophile used in the quenching step. The electrophile can be introduced at either the benzylic position or at the C-2 position in the pyrene nucleus. Furthermore, when H+ was used as the quencher, the product of the intramolecular carbolithiation of the pyrene K-region was formed. Dehydrogenation of the obtained compound with DDQ allowed the synthesis of a novel nitrogen polycyclic compound with an aza-benzo[c,d]pyrene (azaolympicene) skeleton. Attempts to extend the reaction scope to the amides substituted in the phenyl ring 8a and 8b gave an unexpected result. The reaction of both compounds with BuLi gave 1-valerylpyrene (9) in good yield. Photophysical properties, including absorption spectra, emission spectra and quantum yields of the emission of selected products, were studied and discussed.

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Versatile and Direct Transformation of Secondary Amides into Ketones by Deaminative Alkylation with Organocerium Reagents

Cited by 75 publications

References 36 publications

Metal-Free C–H Alkyliminylation and Acylation of Alkenes with Secondary Amides

Metal-Free C–H Alkyliminylation and Acylation of Alkenes with Secondary Amides

Mechanistic Diversity of Low-Valent Chromium Catalysis: Cross-Coupling and Hydrofunctionalization

Electrophile-Dependent Reactivity of Lithiated N-Benzylpyrene-1-Carboxamide

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