Iminoacylation of Alkenes via Photoredox N-Heterocyclic Carbene Catalysis

Dong, Yi-Xiong; Zhang, Chun-Lin; Gao, Zhong‐Hua; Ye, Song

doi:10.1021/acs.orglett.3c00006

Cited by 32 publications

(18 citation statements)

References 62 publications

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“…Light irradiation was essential for this reaction, as it did not progress in dark conditions (entry 8). Noticeably, 37 % of the desired product 3 a was detected when the reaction was performed without using an NHC catalyst (entry 9) [11g,13] . We speculated that this was due to the direct SET between photoexcited xanthate and acyl imidazole 2 a .…”

Section: Resultsmentioning

confidence: 98%

Photoinduced Electron Transfer from Xanthates to Acyl Azoliums: Divergent Ketone Synthesis via N‐Heterocyclic Carbene Catalysis

2023

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Considering the prevalence of alcohols and carboxylic acids, their fragment cross-coupling reactions could hold significant implications in organic synthesis. Herein, we report a versatile method for synthesizing a diverse range of ketones from alcohols and carboxylic acid derivatives via N-heterocyclic carbene (NHC) catalysis. Mechanistic investigations revealed that photoexcited xanthates and acyl azoliums undergo single electron transfer (SET) under photocatalyst-free conditions, generating NHC-derived ketyl radicals and alkyl radicals. These open-shell intermediates subsequently undergo the radical-radical cross-coupling reaction, yielding valuable ketones. Furthermore, this approach can be employed in three-component reactions involving alkenes and enynes, resulting in structurally diverse cross-coupled ketones. The unified strategy offers a unique opportunity for the fragment coupling of a diverse range of alcohols and carboxylic acid derivatives, accommodating diverse functional groups even in complex settings.

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Section: Resultsmentioning

confidence: 98%

Photoinduced Electron Transfer from Xanthates to Acyl Azoliums: Divergent Ketone Synthesis via N‐Heterocyclic Carbene Catalysis

2023

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“…16a,b Considering the latter approach, two elegant processes were developed by Knowles et al in 2015. In their work, carbo-and hydroamination for the synthesis of N-containing heterocycles by applying photoredox catalysis was described (Scheme 1b). 17 During the preparation of this manuscript an aminoacylation and an iminoacylation via N-radical generation by N-O bond cleavage were reported by Zhao et al 18 and Ye et al 19 Inspired by the recent work on cooperative NHC/photoredox catalysis and the amidyl radical chemistry developed by Knowles et al, 17 we decided to combine these two strategies to realize an aminoacylation of alkenes (Scheme 1c).…”

Section: Cluster Synlettmentioning

confidence: 99%

Aminoacylation of Alkenes by Cooperative NHC and Photoredox Catalysis

Lezius¹,

Reimler²,

Döben³

et al. 2023

Synlett

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Cooperative NHC and photoredox catalysis has gained great attention as an emerging research field in recent years. Herein, we report a cyclizing aminoacylation of alkenes, which is enabled through combination of these two catalytic modes. The key step is a radical/radical cross coupling between a persistent ketyl radical and a transient benzylic or aliphatic C-radical, which is generated through radical cyclization of an oxidatively formed amidyl radical. Several carbamates, amides and sulfonamides containing an alkene moiety and different acyl fluorides can be used as substrates. The resulting products are obtained in moderate to good yields.

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“…In this context, Ye and co‐workers developed an iminoacylation of alkenes via dual NHC/photoredox catalysis driven by visible light (Scheme 36). [52] In this protocol, alkene‐tethered α‐imino‐oxy acids acted as the iminyl radical precursor. And the intramolecular addition of iminyl radical in 36‐I to the tethered alkene in a 5‐ exo‐trig manner could give dihydropyrrole‐derived C ‐radical 36‐II , which thus coupled with the NHC‐bound ketyl‐radical delivering the desired product.…”

Section: Radical Acylation Of Alkenes Via Set Reduction Of Nhc‐bound ...mentioning

confidence: 99%

Radical Acylation of Alkenes by NHC‐Organocatalysis

Tang,

Du,

Gao

2023

Eur J Org Chem

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N‐Heterocyclic carbene (NHC) catalyzed radical‐radical reactions have been proven to be powerful strategies for assembling ketyl‐containing compounds via single electron transfer (SET) pathway under either thermal conditions or photoredox conditions. In this context, acylation of alkenes via radical relay under NHC‐organocatalysis has also opened a new window for the difunctionalization of alkenes to construct valuable molecules in organic synthesis. In this review, the advances and progress of the acylation of alkenes via NHC‐organocatalysis were summarized according to different ways of generation of the key NHC‐bound ketyl‐type radicals. Furthermore, reaction scopes, limitations and mechanisms were discussed based on reaction types and catalytic systems. Conclusions and perspectives were also put forward at the end.

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Iminoacylation of Alkenes via Photoredox N-Heterocyclic Carbene Catalysis

Cited by 32 publications

References 62 publications

Photoinduced Electron Transfer from Xanthates to Acyl Azoliums: Divergent Ketone Synthesis via N‐Heterocyclic Carbene Catalysis

Photoinduced Electron Transfer from Xanthates to Acyl Azoliums: Divergent Ketone Synthesis via N‐Heterocyclic Carbene Catalysis

Aminoacylation of Alkenes by Cooperative NHC and Photoredox Catalysis

Radical Acylation of Alkenes by NHC‐Organocatalysis

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