Polymerization-Enhanced Photocatalysis for the Functionalization of C(sp³)–H Bonds

ACS Catalysis, Год журнала: 2021, Номер 12(1), С. 126 - 134

Опубликована: Дек. 13, 2021

A series of conjugated polymetric photocatalysts (CPPs) based on 1,2,3,5-tetrakis(carbazol-9-yl)4,6-dicyanobenzene (4CzIPN) were synthesized via nucleophilic substitution reaction and Sonogashira–Hagihara coupling. Among the as-prepared CPPs (CPP1-CPP6), CPP3 was selected as optimized heterogeneous photocatalyst for visible-light-driven functionalization C(sp3)–H bonds to synthesize 87 final products with yields up 99%. The is easily recovered from excellent retention photocatalytic activity, which can be reused at least five times. Time-dependent density functional theory (TD-DFT) calculations demonstrate that photocatalysis performance superior corresponding monomer 4CzIPN because enhanced intersystem crossing (ISC) process. Spin–orbit coupling prove rate constant ISC outcompetes reverse (RISC). rapidly generated long-lived triplet state T1 considered a more accessible excited than singlet-state S1 either direct excitation or RISC. successful application this polymerization-enhanced strategy should guide metal-free approach rational design CPP-type address dilemma homogeneous in sustainability, stability, recyclability.

Язык: Английский

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Reductive Arylation of Aliphatic and Aromatic Aldehydes with Cyanoarenes by Electrolysis for the Synthesis of Alcohols

Organic Letters, Год журнала: 2021, Номер 23(9), С. 3472 - 3476

Опубликована: Апрель 16, 2021

An electroreductive arylation reaction of aliphatic and aromatic aldehydes as well ketones with electro-deficient (hetero)arenes is described. A variety cyano(hetero)arenes carbonyl compounds, especially aldehydes, have been examined, providing secondary tertiary alcohols in moderate to good yields. Mechanistic studies, including cyclic voltammetry (CV), electron paramagnetic resonance (EPR), divided-cell experiments, support the generation ketyl radicals persistent heteroaryl radical anions via cathodic reduction followed by radical-radical cross-coupling.

Язык: Английский

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Reductive Activation and Hydrofunctionalization of Olefins by Multiphoton Tandem Photoredox Catalysis

ACS Catalysis, Год журнала: 2021, Номер 11(9), С. 5472 - 5480

Опубликована: Апрель 20, 2021

The conversion of olefin feedstocks to architecturally complex alkanes represents an important strategy in the expedient generation valuable molecules for chemical and life sciences. Synthetic approaches are reliant on electrophilic activation unactivated olefins, necessitating functionalization with nucleophiles. However, reductive less activated olefins electrophiles remains ongoing challenge synthetic chemistry. Here, we report nucleophilic inert styrenes through a photoinduced direct single electron reduction corresponding radical anion. Central this approach is multiphoton tandem photoredox cycle iridium photocatalyst [Ir(ppy)2(dtb-bpy)]PF6, which triggers situ formation high-energy photoreductant that selectively reduces styrene olefinic π bonds anions without stoichiometric reductants or dissolving metals. This mild enables chemoselective hydrofunctionalization furnish alkane tertiary alcohol derivatives. Mechanistic studies support anion intermediate Birch-type involving two sequential transfers. Overall, complementary mode achieves alkenes electrophiles, adding value abundant as building blocks modern protocols.

Язык: Английский

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Direct 1,2‐Dicarbonylation of Alkenes towards 1,4‐Diketones via Photocatalysis

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(51), С. 26822 - 26828

Опубликована: Сен. 29, 2021

1,4-Dicarbonyl compounds are intriguing motifs and versatile precursors in numerous pharmaceutical molecules bioactive natural compounds. Direct incorporation of two carbonyl groups into a double bond at both ends is straightforward, but also challenging. Represented herein the first example 1,2-dicarbonylation alkenes by photocatalysis. Key to success that N(n-Bu)4+ not only associates with alkyl anion avoid protonation, activates α-keto acid undergo electrophilic addition. The employed for acyl generation By tuning reductive ability precursor, unsymmetric 1,4-dicarbonylation achieved time. This metal-free, redox-neutral regioselective executed photocatalyst substrates under extremely mild conditions shows great potential biomolecular drug molecular derivatization.

Язык: Английский

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Mild and metal-free Birch-type hydrogenation of (hetero)arenes with boron carbonitride in water

Nature Catalysis, Год журнала: 2022, Номер 5(12), С. 1157 - 1168

Опубликована: Дек. 12, 2022

Язык: Английский

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Transition-Metal-Free, Site-Selective C–F Arylation of Polyfluoroarenes via Electrophotocatalysis

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(37), С. 17261 - 17268

Опубликована: Сен. 7, 2022

Direct CAr-F arylation is effective and sustainable for synthesis of polyfluorobiaryls with different degrees fluorination, which are important motifs in medical material chemistry. However, no aid transition metals, the engagement bond activation has proved difficult. Herein, an unprecedented transition-metal-free strategy reported site-selective polyfluoroarenes simple (het)arenes. By merging N,N-bis(2,6-diisopropylphenyl)perylene-3,4,9,10-bis(dicarboximide)-catalyzed electrophotocatalytic reduction anodic nitroxyl radical oxidation cell, various polyfluoroaromatics (2F-6F 8F), especially inactive partially fluorinated aromatics, undergo sacrificial-reagents-free C-F high regioselectivity, yields comparable to those transition-metal catalysis. This atom- step-economic protocol features a paired electrocatalysis organic mediators both cathodic processes. The broad substrate scope good functional-group compatibility highlight merits this operationally strategy. Moreover, easy gram-scale late-stage functionalization collectively advocate practical value, would promote vigorous development fluorine

Язык: Английский

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Redox-neutral carbon–heteroatom bond formation under photoredox catalysis

Chemical Communications, Год журнала: 2023, Номер 59(46), С. 7004 - 7027

Опубликована: Янв. 1, 2023

This feature article presents all the recent reports on photoredox-catalyzed redox-neutral carbon–heteroatom coupling reactions up to March 2023.

Язык: Английский

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Access to CF₂COR-Containing Quinazolinones via Visible-Light-Induced Domino Difluoroalkylation/Cyclization of N-Cyanamide Alkenes

Organic Letters, Год журнала: 2024, Номер 26(10), С. 2119 - 2123

Опубликована: Март 4, 2024

A green and highly efficient visible-light-induced radical cascade difluoroalkylation/cyclization reaction of N-cyanamide alkenes has been developed. variety CF2COR-containing quinazolinones have obtained in high yields with cheap non-metallic 4CzIPN as the photocatalyst. This photocatalytic provides rapid, facile, practical access to valuable polycyclic quinazolinone, it is amenable gram scale.

Язык: Английский

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Visible-Light-Promoted Metal- and Photocatalyst-Free Reactions between Arylglyoxylic Acids and Tetraalkylthiuram Disulfides: Synthesis of α-Ketoamides

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(3), С. 1473 - 1482

Опубликована: Янв. 16, 2024

A convenient and new synthetic approach has been developed for the oxidative cross-coupling of C–N bond through reaction between arylglyoxylic acids tetraalkylthiuram disulfides. The proceeds under ambient air at room temperature in presence visible light. This offers a metal-, base-, photocatalyst-, solvent-free synthesis various α-ketoamides with moderate to excellent yields via radical pathway. In addition, this protocol demonstrates potential application gram-scale synthesis.

Язык: Английский

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Acridinium Salts and Cyanoarenes as Powerful Photocatalysts: Opportunities in Organic Synthesis

Angewandte Chemie, Год журнала: 2021, Номер 133(36), С. 19678 - 19701

Опубликована: Апрель 22, 2021

Abstract The use of organic photocatalysts has revolutionized the field photoredox catalysis, as it allows access to reactivities that were traditionally restricted transition‐metal photocatalysts. This Minireview reports recent developments in acridinium ions and cyanoarene derivatives synthesis. activation inert chemical bonds well late‐stage functionalization biorelevant molecules are discussed, with a special focus on their mechanistic aspects.

Язык: Английский

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