Radical Decyanations of Unactivated Carbon‐CN Bonds: Recent Achievements and Mechanistic Studies DOI
Jiapian Huang, Zhiyuan Chen

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(13), P. 2058 - 2091

Published: May 17, 2023

Abstract Decyanation is an important process in the synthesis of aromatic molecules studies pharmaceutical research, medical and materials sciences. In late‐stage modifications privileged carbo/heterocyclic scaffolds, radical‐type decyanation techniques have been devised to date. As a result, chemistry cyano‐involved conversions, hotly debated subject over past few decades, has advanced significantly. The cyano group (CN), on other hand, rarely acknowledged as good reaction site due its thermodynamic robustness. most recent advancements catalytic radical protocols that CN behaved leaving made are surveyed this article. Following introduction number different modes, reactions used activate C−CN bonds primarily categorized, text herein divided into three groups: (1) photo‐catalyzed transformations, (2) electro‐catalyzed (3) transition‐metal‐catalyzed or metal‐free transformations. With emphasis systems synthetic applications bond activation, review will provide readers with overview reactions.

Language: Английский

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

Shan‐Shan Zhu,

Yan Liu, Xiaolan Chen

et al.

ACS Catalysis, Journal Year: 2021, Volume and Issue: 12(1), P. 126 - 134

Published: Dec. 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.

Language: Английский

Citations

69
Reductive Arylation of Aliphatic and Aromatic Aldehydes with Cyanoarenes by Electrolysis for the Synthesis of Alcohols DOI
Xiǎo Zhang, Chao Yang, Han Gao

et al.

Organic Letters, Journal Year: 2021, Volume and Issue: 23(9), P. 3472 - 3476

Published: April 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.

Language: Английский

Citations

63
Reductive Activation and Hydrofunctionalization of Olefins by Multiphoton Tandem Photoredox Catalysis DOI
Milena L. Czyz,

Mitchell S. Taylor,

Tyra H. Horngren

et al.

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(9), P. 5472 - 5480

Published: April 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.

Language: Английский

Citations

59
Mild and metal-free Birch-type hydrogenation of (hetero)arenes with boron carbonitride in water DOI
Yuan Tao, Luyang Sun,

Ziwei Wu

et al.

Nature Catalysis, Journal Year: 2022, Volume and Issue: 5(12), P. 1157 - 1168

Published: Dec. 12, 2022

Language: Английский

Citations

58
Direct 1,2‐Dicarbonylation of Alkenes towards 1,4‐Diketones via Photocatalysis DOI
Yuanyuan Cheng,

Jixin Yu,

Tao Lei

et al.

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(51), P. 26822 - 26828

Published: Sept. 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.

Language: Английский

Citations

56
Transition-Metal-Free, Site-Selective C–F Arylation of Polyfluoroarenes via Electrophotocatalysis DOI

Yajing Chen,

Wen‐Hao Deng,

Jia‐Dong Guo

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(37), P. 17261 - 17268

Published: Sept. 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

Language: Английский

Citations

56
Redox-neutral carbon–heteroatom bond formation under photoredox catalysis DOI
Sumit Ghosh, Souvik Majumder, Debashis Ghosh

et al.

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(46), P. 7004 - 7027

Published: Jan. 1, 2023

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

Language: Английский

Citations

29
Access to CF2COR-Containing Quinazolinones via Visible-Light-Induced Domino Difluoroalkylation/Cyclization of N-Cyanamide Alkenes DOI

Yangyang Cui,

Wen Xu,

Wenchao Yang

et al.

Organic Letters, Journal Year: 2024, Volume and Issue: 26(10), P. 2119 - 2123

Published: March 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.

Language: Английский

Citations

15
Visible-Light-Promoted Metal- and Photocatalyst-Free Reactions between Arylglyoxylic Acids and Tetraalkylthiuram Disulfides: Synthesis of α-Ketoamides DOI
Subhankar Kumar Sarkar, Satyajit Pal, Anindita Mukherjee

et al.

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(3), P. 1473 - 1482

Published: Jan. 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.

Language: Английский

Citations

10
Acridinium Salts and Cyanoarenes as Powerful Photocatalysts: Opportunities in Organic Synthesis DOI
Anis Tlili, Sami Lakhdar

Angewandte Chemie, Journal Year: 2021, Volume and Issue: 133(36), P. 19678 - 19701

Published: April 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.

Language: Английский

Citations

50