Catalytic Radical Cation Salt Induced C<sub>sp<sup>3</sup></sub>–H Functionalization of Glycine Derivatives: Synthesis of Substituted Quinolines

Jia, Xiaodong; Peng, Fangfang; Chang, Qing; Huo, Congde; Wang, Xicun

doi:10.1021/ol301909g

Cited by 136 publications

(29 citation statements)

References 33 publications

(11 reference statements)

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“…(6)) and the desired product was isolated in comparable yield (the starting material was recovered in 82 % yield). Above results show that this aerobic oxidation was initiated by a combination of dioxygen and TBPA +⋅ , which is in accord with our proposed mechanism –…”

Section: Methodssupporting

confidence: 90%

“…The yield of this reaction was not affected by the use of 2,4‐disubstituted α‐anilino phosphonates 2 h and 2 k either. In our previous reports, the absence of a para substituent at the aniline dramatically decreased the yield of the desired product,– but in this case N ‐methyl‐ N ‐( m ‐tolyl)formamide ( 2 i ) was obtained in 68 % yield. However, only trace amount of the formylation product was detected by TLC, and about 85 % of the starting material was recovered, when o ‐tolylanilino phosphonate ( 2 j ) was used.…”

Section: Methodsmentioning

confidence: 68%

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Carbonylation of Csp³−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

Zhu

Lü

et al. 2016

Asian J Org Chem

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AW ittig-typer eaction was achieved by radical cation salt induced aerobic oxidation of Csp 3 ÀHb onds. Different from the "standard" version of the Wittig reaction, in which ac arbon-carbon double bond is formed from ac arbonyl, carbonyl groups can be installed by similar process.First reported in 1953, [1] the Wittig olefination reactioni so ne of the most powerful synthetic tools for selectivec onstruction of carbon-carbon doubleb onds.[2] Duet ot he broad applications of this method, the development of novel transformations which utilize new classes of Wittig reagents has attracted much attention in organic synthesis. [3,4] In these elegant modificationsa nd improvements, only two versions of Wittig-type reactions were fully investigated:t he classic Wittig reaction, which can installc arbon-carbon double bonds from aldehydes or ketones (Scheme 1, eq. (a)), and the aza-Wittig reaction (Staudinger reaction), which can construct carbon-nitrogen double bonds from phosphazenes (Scheme 1, eq. (b)), nitrogen based phosphorus ylides. The formation of the four-membered oxaphosphetane intermediate (Scheme 1, intermediate I) is the key step from which the product alkene or Schiff base are released accompanied by the triphenylphosphine oxide byproduct. However,t he separation of the product alkene from the byproduct triphenylphosphine oxide is ac lassical problem and typicallyr equirest edious chromatography or recrystallization. To overcome this problem,t he Horner-Wadsworth-Emmons olefination wasd eveloped, [5] in which the byproduct dialkyl phosphates are water-soluble and more easily separablef rom the alkene products than triphenylphosphine oxide.Recently,C ÀHa ctivation mediated by radical intermediates has attracted considerable attention, and av ariety of methods have been established.[6] As part of our ongoing research project on radical cation initiatedC ÀHb ond functionalization, [7] we are particularly interested in developing an ew process for these phosphorus substrates. We hypothesizedt hat oxidizing Csp 3 ÀHb onds alpha to phosphorus could produce af ree radical that could be captured by dioxygenr esulting in the formation of an oxo-four-membered intermediate (Scheme 1, intermediate I, X = carbon and Y = oxygen).A fter dialkyl phosphate leaves,acarbonyl compound arising from af ormal N-formylation would be afforded (Scheme1,e q. (c)). If feasible, this transformation would be an interesting variant of Wittig reaction, where insteado ff orming olefins from carbonyls, carbonyl groups could be installed throughW ittig-type process.We chose a-anilino phosphonate 1a,w hich can be easily synthesized from the corresponding aniline, formaldehyde and trimethyl phosphite (see the supporting information), as the model substrate to test the possibility of this oxidative Wittig reaction. Our study began with oxidation of 1a initiated by TBPA + · (tris(4-bromophenyl)aminium hexachloroantimonate) in the presence of dioxygen (Table 1). To our delight, the carbonylation occurred smoothly in the presence of 10 ...

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Section: Methodssupporting

confidence: 90%

Section: Methodsmentioning

confidence: 68%

Carbonylation of Csp³−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

Zhu

Lü

et al. 2016

Asian J Org Chem

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“…In the presence of dioxygen, the C−H bond oxidation was initiated by TBPA + . , generating radical intermediate A . After an oxidative Povarov reaction between A and α‐methylstyrene, a tetrahydroquinoline B was formed.…”

Section: Figurementioning

confidence: 99%

A Consecutive C−H Functionalization Triggered by Oxidation of Active sp³ C−H Bonds: Construction of 3,4‐Dihydroquinoline‐3‐one Derivatives

Jia

Hou

Shao

et al. 2017

Chemistry A European J

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“…Since 2012, our group has achieved aseries of sp 3 CÀHf unctionalization by using TBPA + C [tris(4-bromophenyl)aminium hexachloroantimonate]/O 2 catalyst system,c onstructingv arious heterocycles in high efficiency. [13] In this research, TBPA + C exhibited good reactivity to promote the aerobic oxidationo f sp 3 CÀHb ond, and in most cases, av ariety of functional groups can be tolerated. Recently,t his catalysts ystem was further applied to the phosphorylation of glycine derivatives, [12b] and the results showedh igher functional group tolerance and wider reaction scope, compared with reported approaches.…”

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confidence: 74%

Radical Cation Salt‐initiated Aerobic C−H Phosphorylation of N‐Benzylanilines: Synthesis of α‐Aminophosphonates

Jia

Liu

et al. 2018

Chemistry An Asian Journal

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A radical cation salt-initiated phosphorylation of N-benzylanilines was realized through an aerobic oxidation of the sp C-H bond, providing a series of α-aminophosphonates in high yields. An investigation of the reaction scope revealed that this mild catalyst system is superior in good functional group tolerance and high reaction efficiency. The mechanistic study implied that the cleavage of the sp C-H bond was involved in the rate-determining step.

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Catalytic Radical Cation Salt Induced C_sp³–H Functionalization of Glycine Derivatives: Synthesis of Substituted Quinolines

Cited by 136 publications

References 33 publications

Carbonylation of Csp³−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

Carbonylation of Csp³−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

A Consecutive C−H Functionalization Triggered by Oxidation of Active sp³ C−H Bonds: Construction of 3,4‐Dihydroquinoline‐3‐one Derivatives

Radical Cation Salt‐initiated Aerobic C−H Phosphorylation of N‐Benzylanilines: Synthesis of α‐Aminophosphonates

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Catalytic Radical Cation Salt Induced Csp3–H Functionalization of Glycine Derivatives: Synthesis of Substituted Quinolines

Cited by 136 publications

References 33 publications

Carbonylation of Csp3−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

Carbonylation of Csp3−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

A Consecutive C−H Functionalization Triggered by Oxidation of Active sp3 C−H Bonds: Construction of 3,4‐Dihydroquinoline‐3‐one Derivatives

Radical Cation Salt‐initiated Aerobic C−H Phosphorylation of N‐Benzylanilines: Synthesis of α‐Aminophosphonates

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Catalytic Radical Cation Salt Induced C_sp³–H Functionalization of Glycine Derivatives: Synthesis of Substituted Quinolines

Carbonylation of Csp³−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

Carbonylation of Csp³−H Bonds through Oxidative Wittig‐Type Reaction: An Unprecedented Version of Wittig Reaction

A Consecutive C−H Functionalization Triggered by Oxidation of Active sp³ C−H Bonds: Construction of 3,4‐Dihydroquinoline‐3‐one Derivatives