Visible-light photocatalytic activation of N-chlorosuccinimide by organic dyes for the chlorination of arenes and heteroarenes

Rogers, D.; Gallegos, Jillian M.; Hopkins, Megan D.; Lignieres, Austin; Pitzel, Amy K.; Lamar, Angus A.

doi:10.1016/j.tet.2019.130498

Cited by 25 publications

(8 citation statements)

References 45 publications

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“…Despite the lower yield observed in CH 3 CN (Table , entry 4), this solvent was chosen for these measurements because it provided the complete dissolution of all the species involved in the fluorescence quenching experiments, thus ensuring the reproducibility of the measurements. NCS was not able to act as a quencher, even when the reaction conditions were reproduced in the presence of K 2 CO 3 and of the allene, confirming the results reported by König and Lamar. , Thus, an electrophilic amplification of NCS promoted by the oxidative quenching of the excited photocatalyst (PC*) had to be excluded. Furthermore, both allene 1a and N -chloroallene 3a were not able to provide fluorescence quenching.…”

Section: Resultsmentioning

confidence: 99%

Photoinduced Chloroamination Cyclization Cascade with N-Chlorosuccinimide: From N-(Allenyl)sulfonylamides to 2-(1-Chlorovinyl)pyrrolidines

et al. 2022

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Here, we present an intriguing photoinduced chloroamination cyclization of allenes bearing a tethered sulfonylamido group to afford 2-(1-chlorovinyl)pyrrolidines and related heterocycles in the presence of N-chlorosuccinimide (NCS) as the chlorine source. An in depth experimental and computational mechanistic study revealed the existence of multiple reaction pathways leading to a common nitrogen centered radical (NCR). This key NCR can be, in fact, originated from (a) the oxidation of the deprotonated allene by the photoexcited state of the Ru-catalyst and (b) the photodissociation of the in situ formed N-chloroallene. The NCR formation triggers an intramolecular cyclization to a highly reactive pyrrolidine vinyl radical, which upon chlorination delivers the final product. Thus, NCS plays a dual role, serving both as an activator of the sulfonamido functionality and as the chlorinating agent.

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Section: Resultsmentioning

confidence: 99%

Photoinduced Chloroamination Cyclization Cascade with N-Chlorosuccinimide: From N-(Allenyl)sulfonylamides to 2-(1-Chlorovinyl)pyrrolidines

et al. 2022

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“…(7) Although a benzylic radical would react with NCS directly to afford benzylic chloride resulting in the radical chain propagation process, the time profile of benzylic chlorination using diphenylmethane 1l as the substrate revealed that continuous visible light irradiation was necessary to this photocatalytic transformation, and the propagating chain reaction was short-lived (Figure S7). As the oxidation potential of NCS is +1.10 V vs SCE and the reduction potential of Acr • -Mes •+ is +1.88 V vs SCE, we therefore speculated that Acr • -Mes •+ would oxidize NCS regenerating Acr • -Mes, which restarted the short chain propagation under illumination.…”

Section: Results and Discussionmentioning

confidence: 99%

Visible Light-Catalyzed Benzylic C–H Bond Chlorination by a Combination of Organic Dye (Acr⁺-Mes) and N-Chlorosuccinimide

et al. 2020

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By combining “N-chlorosuccinimide (NCS)” as the safe chlorine source with “Acr+-Mes” as the photocatalyst, we successfully achieved benzylic C–H bond chlorination under visible light irradiation. Furthermore, benzylic chlorides could be converted to benzylic ethers smoothly in a one-pot manner by adding sodium methoxide. This mild and scalable chlorination method worked effectively for diverse toluene derivatives, especially for electron-deficient substrates. Careful mechanistic studies supported that NCS provided a hydrogen abstractor “N-centered succinimidyl radical,” which was responsible for the cleavage of the benzylic C–H bond, relying on the reducing ability of Acr•-Mes.

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“…Lamar and his co-workers developed chlorination of arenes and heteroarenes using organic dyes as visible light photoredox catalysts in 2019 [ 53 ]. The reaction was carried out via treatment with NCS as a chlorine source in the presence of methylene green as an organic dye photocatalyst under irradiation of a white LED in acetonitrile ( Scheme 49 ).…”

Section: Photo-catalyzed Halogenations Of Aromatic C-h Bondsmentioning

confidence: 99%

Visible-Light-Induced Catalytic Selective Halogenation with Photocatalyst

2021

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Halide moieties are essential structures of compounds in organic chemistry due to their popularity and wide applications in many fields such as natural compounds, agrochemicals, and pharmaceuticals. Thus, many methods have been developed to introduce halides into various organic molecules. Recently, visible-light-driven reactions have emerged as useful methods of organic synthesis. Particularly, halogenation strategies using visible light have significantly improved the reaction efficiency and reduced toxicity, as well as promoted reactions under mild conditions. In this review, we have summarized recent studies in visible-light-mediated halogenation (chlorination, bromination, and iodination) with photocatalysts.

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Visible-light photocatalytic activation of N-chlorosuccinimide by organic dyes for the chlorination of arenes and heteroarenes

Cited by 25 publications

References 45 publications

Photoinduced Chloroamination Cyclization Cascade with N-Chlorosuccinimide: From N-(Allenyl)sulfonylamides to 2-(1-Chlorovinyl)pyrrolidines

Photoinduced Chloroamination Cyclization Cascade with N-Chlorosuccinimide: From N-(Allenyl)sulfonylamides to 2-(1-Chlorovinyl)pyrrolidines

Visible Light-Catalyzed Benzylic C–H Bond Chlorination by a Combination of Organic Dye (Acr⁺-Mes) and N-Chlorosuccinimide

Visible-Light-Induced Catalytic Selective Halogenation with Photocatalyst

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Visible-light photocatalytic activation of N-chlorosuccinimide by organic dyes for the chlorination of arenes and heteroarenes

Cited by 25 publications

References 45 publications

Photoinduced Chloroamination Cyclization Cascade with N-Chlorosuccinimide: From N-(Allenyl)sulfonylamides to 2-(1-Chlorovinyl)pyrrolidines

Photoinduced Chloroamination Cyclization Cascade with N-Chlorosuccinimide: From N-(Allenyl)sulfonylamides to 2-(1-Chlorovinyl)pyrrolidines

Visible Light-Catalyzed Benzylic C–H Bond Chlorination by a Combination of Organic Dye (Acr+-Mes) and N-Chlorosuccinimide

Visible-Light-Induced Catalytic Selective Halogenation with Photocatalyst

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Visible Light-Catalyzed Benzylic C–H Bond Chlorination by a Combination of Organic Dye (Acr⁺-Mes) and N-Chlorosuccinimide