Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reactions of (Benz)oxazoles with Ethers

Li, Yanrong; Wang, Mengshi; Fan, Wei; Qian, Fen; Li, Guigen; Lü, Hongjian

doi:10.1021/acs.joc.6b02211

Cited by 69 publications

(28 citation statements)

References 70 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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“…[128] Acyclice thers,i nw hich more than one CÀHb ond can be activated, usually yield mixtures of regioisomers.The addition of tetrahydrofuran (as well as 2-methyltetrahydrofuran and 1,4-dioxane) on 8-H-purines could also be achieved using (1)].…”

Section: Alkylation By Cross-dehydrogenative Coupling With Alkanes Ementioning

confidence: 99%

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

2019

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The alkylation of arenes is one of the most fundamental transformations in chemical synthesis leading to privileged scaffolds in many areas of science. Classical methods for the introduction of alkyl groups to arenes are mostly based on the Friedel-Crafts reaction, radical additions, metallation or pre-functionalization of the arene: these methods however suffer from limitations in scope, efficiency and selectivity. Moreover, they are based on the innate reactivity of the starting arene, favoring the alkylation at a certain position and rendering the introduction of alkyl chains at other positions much more challenging. This can be addressed by the use of a directing group facilitating, in the presence of a metal catalyst, the regioselective alkylation of a C-H bond. These directed alkylations of C-H bonds in arenes are overviewed, in a comprehensive manner, in this review article.

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“…The direct alkylation of (benz)oxazoles with cyclic ethers, as well as with some acyclic ones, were indeed achieved by Li and Lu by using CoCO 3 and excess TBHP as catalyst and oxidant, to afford the desired products in good yields through a radical pathway [Scheme , Eq. (1)] . Acyclic ethers, in which more than one C−H bond can be activated, usually yield mixtures of regioisomers.…”

Section: Alkylation Of Heteroarenesmentioning

confidence: 99%

Beyond Friedel and Crafts: Innate Alkylation of C−H Bonds in Arenes

Evano

Theunissen

2019

Angew Chem Int Ed

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Alkylated arenes are ubiquitous molecules and building blocks commonly utilized in most areas of science where there is a need for small organic molecules. Despite its apparent simplicity, the regioselective alkylation of arenes is still a challenging transformation in a lot of cases. Classical methods for the introduction of alkyl groups on arenes, which include the venerable Friedel-Crafts reaction, radical additions, metallation or pre-functionalization of the arene, as well as alternatives such as the directed alkylation of C-H bonds, still suffer from severe limitations in terms of scope, efficiency and selectivity. This can be addressed by exploiting the innate reactivity of some (hetero)arenes, in which electronic and steric properties, governed (or not) by the presence of one (or multiple) heteroatom(s) ensure high levels of regioselectivity. These innate alkylations of C-H bonds in (hetero)arenes will be overviewed, in a comprehensive manner, in this review article.

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Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reactions of (Benz)oxazoles with Ethers

Cited by 69 publications

References 70 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

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

Beyond Friedel and Crafts: Innate Alkylation of C−H Bonds in Arenes

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Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reactions of (Benz)oxazoles with Ethers

Cited by 69 publications

References 70 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

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

Beyond Friedel and Crafts: Innate Alkylation of C−H Bonds in Arenes

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Product

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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