Photoinduced single electron transfer activation of organophosphines: Nucleophilic trapping of phosphine radical cation

Pandey, Ganesh; Pooranchand, D.; Bhalerao, U. T.

doi:10.1016/s0040-4020(01)96916-9

Cited by 78 publications

(50 citation statements)

References 16 publications

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“…Pandey and co-workers first reported a photocatalyzed oxidation of triphenylphosphine to triphenylphosphine oxide in 1991 ( Scheme 11 ). 26 Photoexcitation of dicyanonaphthalene (DCN) by UV light, afforded an excited singlet state species DCN* ( E S1 red = +2.30 V vs SCE) able to promote the single electron oxidation of PPh 3 ( E 1/2 = +0.98 V vs SCE), affording phosphine radical cation 81 . Next, water present in the MeCN reaction solvent, was shown to attack triphenylphosphine radical cation 81 via a two-electron, ionic pathway, affording triphenylphosphoranyl radical 82 .…”

Section: Nucleophile Addition Into a Phosphorus Radical Cationmentioning

confidence: 99%

Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis

et al. 2020

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Photocatalytic generation of phosphoranyl radicals is fast emerging as an essential method for the generation of diverse and valuable radicals, typically via deoxygenation or desulfurization processes. This Perspective is a comprehensive evaluation of all studies using phosphoranyl radicals as tunable mediators in photoredox catalysis, highlighting how two distinct methods for phosphoranyl radical formation (radical addition and nucleophilic addition) can be used to generate versatile radical intermediates with diverse reactivity profiles.

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Section: Nucleophile Addition Into a Phosphorus Radical Cationmentioning

confidence: 99%

Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis

et al. 2020

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“…SET reduction of Ir IV (dF-ppy) 3 [E 1/2 (Ir IV /Ir III ) =+1.18 Vvs. SCE in CH 3 CN] [21] with PMePh 2 [E 1/2 ox =+1.04 Vv s. SCE in CH 3 CN,s ee Supporting Information] [22] regenerates Ir III (dF-ppy) 3 and finishes this catalytic cycle. [23] Subsequently,a ddition of the SCF 3 radical to alkenes 1 forms radical-intermediate C,which is then reduced by PMePh 2 to afford anion intermediate D.…”

Section: Angewandte Chemiementioning

confidence: 99%

Hydrotrifluoromethylthiolation of Unactivated Alkenes and Alkynes with Trifluoromethanesulfonic Anhydride through Deoxygenative Reduction and Photoredox Radical Processes

Ouyang

Qing

2019

Angew Chem Int Ed

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An ongoing challenge in trifluoromethylthiolation reactions is the use of less expensive and easily available trifluoromethylthio sources. Herein, we disclose an unprecedented usage of trifluoromethanesulfonic anhydride (Tf2O) as a radical trifluoromethylthiolating reagent. Hydrotrifluoromethylthiolation of unactivated alkenes and alkynes with Tf2O in the presence of PMePh2 and H2O under visible‐light photoredox catalysis gave the addition products. The trifluoromethylthio radical (.SCF3) was first formed from Tf2O through a photoredox radical processes and deoxygenative reduction of PMePh2, and H2O serves as the H‐atom donor for the hydrotrifluoromethylthiolation reaction. This reaction provides a new strategy for radical trifluoromethylthiolation.

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“…8f . The photoexcited *Ir(dF(CF 3 )ppy) 2 (dtbbpy)]PF 6 [ E 1/2 red (*Ir III /Ir II ) = +1.21 V vs SCE; τ = 2.3 μs] 49 is able to undergo single-electron transfer (SET) oxidation with Ph 3 P ( E 1/2 red = +0.98 V vs SCE) 50 to form the triphenylphosphine radical cation ( 31 ), which could trigger the proposed radical deoxygenation 51 . The resulting radical cation ( 31 ) reacts with carboxylate anion to generate the phosphoryl radical ( 32 ).…”

Section: Resultsmentioning

confidence: 99%

A general deoxygenation approach for synthesis of ketones from aromatic carboxylic acids and alkenes

2018

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The construction of an aryl ketone structural unit by means of catalytic carbon–carbon coupling reactions represents the state-of-the-art in organic chemistry. Herein we achieved the direct deoxygenative ketone synthesis in aqueous solution from readily available aromatic carboxylic acids and alkenes, affording structurally diverse ketones in moderate to good yields. Visible-light photoredox catalysis enables the direct deoxygenation of acids as acyl sources with triphenylphosphine and represents a distinct perspective on activation. The synthetic robustness is supported by the late-stage modification of several pharmaceutical compounds and complex molecules. This ketone synthetic strategy is further applied to the synthesis of the drug zolpidem in three steps with 50% total yield and a concise construction of cyclophane-braced 18–20 membered macrocycloketones. It represents not only the advancement for the streamlined synthesis of aromatic ketones from feedstock chemicals, but also a photoredox radical activation mode beyond the redox potential of carboxylic acids.

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Photoinduced single electron transfer activation of organophosphines: Nucleophilic trapping of phosphine radical cation

Cited by 78 publications

References 16 publications

Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis

Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis

Hydrotrifluoromethylthiolation of Unactivated Alkenes and Alkynes with Trifluoromethanesulfonic Anhydride through Deoxygenative Reduction and Photoredox Radical Processes

A general deoxygenation approach for synthesis of ketones from aromatic carboxylic acids and alkenes

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