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Merging Photoredox PCET with Ni-Catalyzed Cross-Coupling: Cascade Amidoarylation of Unactivated Olefins
摘要： A rapid, highly diastereoselective amidoarylation of unactivated olefins was achieved to render medicinally privileged pyrrolidinone structures. Taking advantage of a photoredox proton-coupled electron transfer process, amidyl radicals were obtained from non-prefunctionalized N–H bonds under mild conditions, which were subsequently trapped by pendant olefins, delivering alkyl radicals for nickel-catalyzed cross-coupling. Mechanistic studies revealed the key balance between thermodynamically-driven radical generation and kinetically-driven cyclization, which led to expanding the scope toward urea and carbamate substrates.
关键词： urea,nickel catalysis,carbamate,unactivated olefins,proton-coupled electron transfer,amidoarylation,photoredox catalysis,pyrrolidinone
更新于2025-09-23 15:23:52
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C5-Selective Trifluoromethylation of 8-Amino quinolines via Photoredox Catalysis
摘要： A new protocol for C5-selective C–H trifluoromethylation of 8-aminoquinolines via photoredox catalysis was developed. It allows rapid access to various C5-trifluoromethyl 8-amino quinoline derivatives in MeCN/H2O enabled by Eosin Y as photocatalysts.
关键词： para-selective C-H activation,Photoredox catalysis,Trifluoromethylation,8-Aminoquinolines
更新于2025-09-23 15:23:52
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<i>N</i> -Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes
摘要： A new range of N-phenylphenothiazine derivatives was synthesized as potential photoredox catalysts to broaden the substrate scope for the nucleophilic addition of methanol to styrenes through photoredox catalysis. These N-phenylphenothiazines differ by their electron-donating and electron-withdrawing substituents at the phenyl group, covering both, σ and π-type groups, in order to modulate their absorbance and electrochemical characteristics. Among the synthesized compounds, alkylaminylated N-phenylphenothiazines were identified to be highly suitable for photoredox catalysis. The dialkylamino substituents of these N-phenylphenothiazines shift the estimated excited state reduction potential up to ?3.0 V (vs SCE). These highly reducing properties allow the addition of methanol to α-methylstyrene as less-activated substrate for this type of reaction. Without the help of an additive, the reaction conditions were optimized to achieve a quantitative yield for the Markovnikov-type addition product after 20 h of irradiation.
关键词： redox potential,photochemistry,addition,photoredox catalysis,phenothiazine
更新于2025-09-23 15:22:29
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Anti-Markovnikov Hydroazidation of Alkenes by Visible Light Photoredox Catalysis
摘要： The anti-Markovnikov hydroazidation of alkenes has been accomplished using [Ir(dF(CF3)ppy)2(dtbbpy)]PF6 as photocatalyst and trimethylsilyl azide as azidating agent. The reactions were greatly facilitated by water, whose beneficial effect can be attributed to its participation in the reaction as the hydrogen donor, as indicated by deuterium isotope experiments. The reactions can be effected under solvent free conditions in the presence of water. 4-Dimethylaminopyridine also exhibited a beneficial effect on the reactions. The present method enabled hydroazidation of several types of unactivated alkenes with good yield and high regionselectivity.
关键词： hydroazidation,water,trimethylsilyl azide,radical reactions,photoredox catalysis
更新于2025-09-23 15:22:29
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Visible Light Driven Reductive (Cyclo)Dimerization of Chalcones Over Heterogeneous Carbon Nitride Photocatalyst
摘要： Single electron reduction of chalcones to the respective radical anions is a useful technique to activate these molecules toward subsequent transformations. Herein, a metal free photocatalytic version of chalcones reduction in the presence of triethanolamine as a convenient electron donor and using heterogeneous carbon nitride visible light photocatalyst is presented. The reaction proceeds via a long lived radical species of the heterogeneous organic semiconductor. The scope of the reaction was studied and regioselectivity of the chalcone radicals coupling was investigated. (1) Ten chalcones gave selectively poly substituted cyclopentanoles with 31-73% isolated yield; (2) Two chalcones bearing electron-donor groups, 4-MeOC6H4 and 2-thienyl, gave selectively the β-ketodienes in 42% and 53% isolated yield, respectively; (3) Pentafluorophenyl substituted chalcone gave exclusively the product of the radicals coupling followed by hydrogen transfer from triethanolamine – hexane-1,6-dione in 65% isolated yield. Reductive cross cyclodimerization of a mixture of two different chalcones proceeded regioselectively with the formation of one product out of four possible. The mechanism was investigated by cyclic voltammetry and linear sweep voltammetry and suggests that the reaction proceed through proton coupled electron transfer.
关键词： cyclopetanole,organic photoredox catalysis,chalcone,carbon nitride,proton coupled electron transfer
更新于2025-09-23 15:22:29
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RECENT APPLICATIONS IN ORGANIC SYNTHESIS OF VISIBLE LIGHT PHOTOREDOX CATALYSIS
摘要： RECENT APPLICATIONS IN ORGANIC SYNTHESIS OF VISIBLE LIGHT PHOTOREDOX CATALYSIS. In the past few years, photoredox catalysis has become a powerful tool in the field of organic synthesis. Using this efficient method, it is possible to excite organic compounds from visible light and attain alternative mechanistic pathways for the formation of chemical bonds, a result which is not obtainable by classical methods. The rapid growth of work in the area of photoredox catalysis is due to its low cost, broad chemical utility protocols, and, especially, its relevancy from the green and sustainable chemistry viewpoints. Thus, this study proposes a brief theoretical discussion of and highlights recent advances in visible-light-induced photoredox catalysis through the analysis of catalytic cycles and intermediates.
关键词： visible light,photoredox catalysis,organocatalysis,organic synthesis,transition metals
更新于2025-09-23 15:21:21
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Photocatalytic Oxyamination of Alkenes: Copper(II) Salts as Terminal Oxidants in Photoredox Catalysis
摘要： A photocatalytic method for the oxyamination of alkenes using simple nucleophilic nitrogen atom sources in place of prefunctionalized electrophilic nitrogen atom donors is reported. Copper(II) is an inexpensive, practical, and uniquely effective terminal oxidant for this process. In contrast to oxygen, peroxides, and similar oxidants commonly utilized in non-photochemical oxidative methods, the use of copper(II) as a terminal oxidant in photoredox reactions avoids the formation of reactive heteroatom-centered radical intermediates that can be incompatible with electron-rich functional groups. As a demonstration of the generality of this concept, it has been shown that diamination and deoxygenation reactions can also be accomplished using similar photooxidative conditions.
关键词： copper(II),photoredox catalysis,alkenes,oxyamination,terminal oxidant,photocatalytic
更新于2025-09-23 15:21:21
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Blue LED-Promoted Oxathiacetalization of Aldehydes and Ketones
摘要： In synthetic chemistry, the protection of aldehydes and ketones is crucial during multistep synthesis of complex molecules. Organic chemists have paid substantial attention to the synthesis of 1,3-oxathiolanes and 1,3-oxathianes because of their considerable stability under acidic conditions and ease of removal of protecting groups. In this paper, we report the mild and efficient oxathiacetalization of aldehydes with 2-mercaptoethanol and 3-mercaptopropan-1-ol through visible-light-promoted eosin–Y catalyzed C–S and C–O bond formation at ambient temperature under metal-free conditions. This catalytic system also affords oxathiacetalization of ketones through photoredox catalysis.
关键词： Ketones,Photoredox catalysis,Mercaptoalcohol,Aldehydes,Oxathiacetalization
更新于2025-09-23 15:21:01
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Visible-Light-Mediated Photoredox-Catalyzed Regio- and Stereoselective Chlorosulfonylation of Alkynes
摘要： Herein, a one-step chlorosulfonylation of alkynes via a photocatalytic redox process is described. A variety of commercially available sulfonyl chlorides can be applied for the generation of sulfonyl radical species under visible-light irradiation. Regio- and stereoselective addition of the sulfonyl radical and chloride leads to the e?cient formation of (E)-selective β-chlorovinyl sulfones from a broad range of terminal and internal alkynes. The reported method represents an operationally simple and mild way to furnish vinyl sulfones.
关键词： photoredox catalysis,vinyl sulfones,chlorosulfonylation,alkynes,visible-light irradiation
更新于2025-09-23 15:21:01
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Enantioselective ?±-Allylation of Anilines Enabled by a Combined Palladium and Photoredox Catalytic System
摘要： An enantioselective and branch-regioselective α-allylation of N-methyl anilines under dual palladium/photoredox catalysis is described. Readily available N-methyl anilines are used as formal “hard” alkyl nucleophiles without pre-activation. Acetic acid is the only side product, which leads to high atom economy of this reaction. This protocol shows good functional group tolerance and broad scope. A range of chiral homoallylic amines were prepared in moderate to good yields (up to 76%), excellent regio- (B:L > 95:5 in all cases) and enantioselectivities (up to 96% ee) under mild reaction conditions.
关键词： asymmetric allylation,photochemistry,photoredox catalysis,cooperative catalysis,palladium
更新于2025-09-23 15:19:57