Copper-catalyzed oxidative C(sp<sup>3</sup>)–H/N–H coupling of sulfoximines and amides with simple alkanes via a radical process

Teng, Fan; Sun, Song; Jiang, Yan; Yu, Jin‐Tao; Cheng, Jiang

doi:10.1039/c5cc00839e

Cited by 91 publications

(32 citation statements)

References 56 publications

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“…In addition, MS analysis indicated the presence of 2,2,6,6-tetramethyl-1-(tetrahydrofuran-2-yloxy) piperidine as an intermediate in the reaction mixture (Scheme 2a). On the basis of all these results and previous reports, [8,[43][44][45][46][47] a reaction pathway is proposed as described in Scheme 2b. Initially, tert-butoxy radical would be formed through the cleavage of DTBP with the assistance of the perovskite catalyst.…”

Section: S C H E M Esupporting

confidence: 61%

Direct oxidative C(sp³)─H/C(sp²)─H coupling reaction using recyclable Sr‐doped LaCoO₃ perovskite catalyst

Trinh

Tran

Nguyễn

et al. 2020

Applied Organom Chemis

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A strontium‐doped lanthanum cobaltite perovskite, La0.6Sr0.4CoO3, was prepared and utilized as a recyclable heterogeneous catalyst for the direct oxidative C(sp3)─H/C(sp2)─H coupling reaction between cyclic ethers and alkenes or coumarins to achieve corresponding α‐functionalized ethers. The α‐functionalization of cyclic thioethers or amides with alkenes or coumarins was also achieved via this protocol. The La0.6Sr0.4CoO3 catalyst exhibited better performance than a variety of homogeneous and heterogeneous catalysts. Utilizing a recyclable catalyst would offer a greener option for the direct oxidative C(sp3)─H/C(sp2)─H coupling reaction. To our best knowledge, the C(sp3)─H/C(sp2)─H coupling between olefins and ethers to generate α‐functionalized ethers using a heterogeneous catalyst has not been previously reported, and the α‐functionalization of cyclic thioethers or amides with alkenes or coumarins is new.

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Section: S C H E M Esupporting

confidence: 61%

Direct oxidative C(sp³)─H/C(sp²)─H coupling reaction using recyclable Sr‐doped LaCoO₃ perovskite catalyst

Trinh

Tran

Nguyễn

et al. 2020

Applied Organom Chemis

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“…In the experiment, the addition of Cu(acac) 2 facilitated the transformation21. To determine its role in this reaction, the interaction between the existing radicals and Cu(acac) 2 was studied.…”

Section: Resultsmentioning

confidence: 99%

Stabilization of Two Radicals with One Metal: A Stepwise Coupling Model for Copper-Catalyzed Radical–Radical Cross-Coupling

Zhu

Bai

et al. 2017

Sci Rep

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Transition metal-catalyzed radical–radical cross-coupling reactions provide innovative methods for C–C and C–heteroatom bond construction. A theoretical study was performed to reveal the mechanism and selectivity of the copper-catalyzed C–N radical–radical cross-coupling reaction. The concerted coupling pathway, in which a C–N bond is formed through the direct nucleophilic addition of a carbon radical to the nitrogen atom of the Cu(II)–N species, is demonstrated to be kinetically unfavorable. The stepwise coupling pathway, which involves the combination of a carbon radical with a Cu(II)–N species before C–N bond formation, is shown to be probable. Both the Mulliken atomic spin density distribution and frontier molecular orbital analysis on the Cu(II)–N intermediate show that the Cu site is more reactive than that of N; thus, the carbon radical preferentially react with the metal center. The chemoselectivity of the cross-coupling is also explained by the differences in electron compatibility of the carbon radical, the nitrogen radical and the Cu(II)–N intermediate. The higher activation free energy for N–N radical–radical homo-coupling is attributed to the mismatch of Cu(II)–N species with the nitrogen radical because the electrophilicity for both is strong.

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“…[292] Calculations supported the suggested combination of the alkyl radical with the amine ligand, which is referred to as "radical capture"a nd can be considered as aformal homolytic substitution at nitrogen. [290] Based on this seminal work, other radical Cu-catalyzed CÀN bond formations at activated CÀHs ites with amides,s ulfonamides,i mides, [293] carbamates, [294] sulfoximines, [295] and Weinreb amides [296] as the nucleophilic Nsources have been developed. Recently,c arboxylic acids in combination with alkyl chlorides [297] and hypervalent iodine [298] were established in such couplings.M oreover,s uch aminations can be combined with ar adical addition to aC =Cd ouble bond where uncatalyzed radical C À Cb ond formation precedes the Cucatalyzed C À Nbond formation.…”

Section: Coppermentioning

confidence: 99%

The Persistent Radical Effect in Organic Synthesis

2019

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Radical–radical couplings are mostly nearly diffusion‐controlled processes. Therefore, the selective cross‐coupling of two different radicals is challenging and not a synthetically valuable transformation. However, if the radicals have different lifetimes and if they are generated at equal rates, cross‐coupling will become the dominant process. This high cross‐selectivity is based on a kinetic phenomenon called the persistent radical effect (PRE). In this Review, an explanation of the PRE supported by simulations of simple model systems is provided. Radical stabilities are discussed within the context of their lifetimes, and various examples of PRE‐mediated radical–radical couplings in synthesis are summarized. It is shown that the PRE is not restricted to the coupling of a persistent with a transient radical. If one coupling partner is longer‐lived than the other transient radical, the PRE operates and high cross‐selectivity is achieved. This important point expands the scope of PRE‐mediated radical chemistry. The Review is divided into two parts, namely 1) the coupling of persistent or longer‐lived organic radicals and 2) “radical–metal crossover reactions”; here, metal‐centered radical species and more generally longer‐lived transition‐metal complexes that are able to react with radicals are discussed—a field that has flourished recently.

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Copper-catalyzed oxidative C(sp³)–H/N–H coupling of sulfoximines and amides with simple alkanes via a radical process

Cited by 91 publications

References 56 publications

Direct oxidative C(sp³)─H/C(sp²)─H coupling reaction using recyclable Sr‐doped LaCoO₃ perovskite catalyst

Direct oxidative C(sp³)─H/C(sp²)─H coupling reaction using recyclable Sr‐doped LaCoO₃ perovskite catalyst

Stabilization of Two Radicals with One Metal: A Stepwise Coupling Model for Copper-Catalyzed Radical–Radical Cross-Coupling

The Persistent Radical Effect in Organic Synthesis

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Copper-catalyzed oxidative C(sp3)–H/N–H coupling of sulfoximines and amides with simple alkanes via a radical process

Cited by 91 publications

References 56 publications

Direct oxidative C(sp3)─H/C(sp2)─H coupling reaction using recyclable Sr‐doped LaCoO3 perovskite catalyst

Direct oxidative C(sp3)─H/C(sp2)─H coupling reaction using recyclable Sr‐doped LaCoO3 perovskite catalyst

Stabilization of Two Radicals with One Metal: A Stepwise Coupling Model for Copper-Catalyzed Radical–Radical Cross-Coupling

The Persistent Radical Effect in Organic Synthesis

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Copper-catalyzed oxidative C(sp³)–H/N–H coupling of sulfoximines and amides with simple alkanes via a radical process

Direct oxidative C(sp³)─H/C(sp²)─H coupling reaction using recyclable Sr‐doped LaCoO₃ perovskite catalyst

Direct oxidative C(sp³)─H/C(sp²)─H coupling reaction using recyclable Sr‐doped LaCoO₃ perovskite catalyst