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

Photocatalytic Cross-Couplings of Aryl Halides Enabled by o-Phosphinophenolate and o-Phosphinothiophenolate DOI

Ni Shen,

Run‐Han Li, Can Liu

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(5), P. 2788 - 2795

Published: Feb. 11, 2022

o-Phosphinophenolate and o-phosphinothiophenolate are potent photocatalysts with strong reducing ability to activate aryl chlorides bromides under visible light for borylation, arylation, phosphorylation. Experimental theoretical studies revealed that the o-diphenylphosphino substituent results in a narrow optical gap facilitates intersystem crossing access triplet states, which promote phenolate thiophenolate function as effective visible-light-photoredox catalysts. The presented herein suggest promising utility of synthetically modified phenolates thiophenolates photoredox

Language: Английский

Citations

47
Photochemical Organocatalytic Functionalization of Pyridines via Pyridinyl Radicals DOI Creative Commons
Emilien Le Saux,

Eleni Georgiou,

Igor A. Dmitriev

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 145(1), P. 47 - 52

Published: Dec. 27, 2022

We report a photochemical method for the functionalization of pyridines with radicals derived from allylic C–H bonds. Overall, two substrates undergo to form new C(sp2)–C(sp3) bond. The chemistry harnesses unique reactivity pyridinyl radicals, generated upon single-electron reduction pyridinium ions, which effective coupling radicals. This novel mechanism enables distinct positional selectivity pyridine that diverges classical Minisci chemistry. Crucial was identification dithiophosphoric acid masters three catalytic tasks, sequentially acting as Brønsted protonation, single electron transfer (SET) reductant ion reduction, and hydrogen atom abstractor activation C(sp3)–H resulting then couple high regioselectivity.

Language: Английский

Citations

43
Sensitizer-controlled photochemical reactivityviaupconversion of red light DOI Creative Commons
Felix Glaser, Oliver S. Wenger

Chemical Science, Journal Year: 2022, Volume and Issue: 14(1), P. 149 - 161

Published: Dec. 1, 2022

By combining the energy input from two red photons, chemical reactions that would normally require blue or ultraviolet irradiation become accessible. Key advantages of this biphotonic excitation strategy are light usually penetrates deeper into complex reaction mixtures and causes less photo-damage than direct illumination in ultraviolet. Here, we demonstrate primary light-absorber a dual photocatalytic system comprised transition metal-based photosensitizer an organic co-catalyst can completely alter outcome. Photochemical reductions achieved with copper(i) presence sacrificial electron donor, whereas oxidative substrate activation occurs osmium(ii) photosensitizer. Based on time-resolved laser spectroscopy, changeover photochemical reactivity is due to different underlying mechanisms. Following triplet transfer 9,10-dicyanoanthracene (DCA) subsequent triplet-triplet annihilation upconversion, fluorescent singlet excited state DCA triggers activation, which initiates

Language: Английский

Citations

41
A General Light‐Driven Organocatalytic Platform for the Activation of Inert Substrates DOI Creative Commons
Shuo Wu, Florian Schiel, Paolo Melchiorre

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: June 16, 2023

Due to their strong covalent bonds and low reduction potentials, activating inert substrates is challenging. Recent advances in photoredox catalysis offered a number of solutions, each which useful for specific bonds. Developing general catalytic platform that can consistently target broad range would be synthetically useful. Herein, we report readily available indole thiolate organocatalyst that, upon excitation with 405 nm light, acquires strongly reducing power. This excited-state reactivity served activate, by single-electron reduction, C-F, C-Cl, C-O both aromatic aliphatic substrates. was versatile enough promote the generally recalcitrant electron-rich (Ered <-3.0 V vs SCE), including arenes afforded 1,4-cyclohexadienes. The protocol also borylation phosphorylation high functional group tolerance. Mechanistic studies identified an anion as responsible highly reactivity.

Language: Английский

Citations

40
Electrophotocatalytic Reductive 1,2‐Diarylationof Alkenes with Aryl Halides and Cyanoaromatics DOI

Liang Zeng,

Jing‐Hao Qin,

Gui‐Fen Lv

et al.

Chinese Journal of Chemistry, Journal Year: 2023, Volume and Issue: 41(16), P. 1921 - 1930

Published: April 7, 2023

Comprehensive Summary The radical‐mediated reductive functionalization of aryl halides has been extensively studied. However, the related intermolecular 1,2‐diarylation alkenes, using as radical sources, remains unexplored. Herein, a new electrophotocatalytic alkenes is reported and cyanoaromatics to produce polyarylated alkanes. Using synergistic cathodic reduction visible‐light photoredox catalysis, various electron‐rich electron‐deficient are combined with characterize broad substrate scope, excellent functional group compatibility, selectivity this reaction. Mechanistic investigations reveal that reaction may proceed via process initiated by generation radicals from terminated radical‐radical coupling cyanoaromatic anions.

Language: Английский

Citations

34
Light-Induced Activation of C–X Bond via Carbonate-Assisted Anion−π Interactions: Applications to C–P and C–B Bond Formation DOI
Vishal Jyoti Roy, Sudipta Raha Roy

Organic Letters, Journal Year: 2023, Volume and Issue: 25(6), P. 923 - 927

Published: Feb. 8, 2023

We have presented a carbonate anion assisted photochemical protocol for the C-X bond activation. Anion-π interactions been leveraged to generate aryl radicals from easily accessible halides that are further utilized in C-P and C-B formation reactions with excellent reactivity broad functional group tolerance. Spectroscopic investigations DFT studies were conducted mechanistic insights. This inexpensive method alleviates use of photocatalyst need preactivation substrate light-induced activation bonds.

Language: Английский

Citations

33
Transition metal-free photochemical C–F activation for the preparation of difluorinated-oxindole derivatives DOI Creative Commons
Bianca T. Matsuo, Jadab Majhi, Albert Granados

et al.

Chemical Science, Journal Year: 2023, Volume and Issue: 14(9), P. 2379 - 2385

Published: Jan. 1, 2023

The development of strategies for single and selective C-F bond activation represents an important avenue to overcome limitations in the synthesis valuable fluorine-containing compounds. synthetic medicinal research communities would benefit from new routes that access such relevant molecules a simple manner. Herein we disclose straightforward mechanistically distinct pathway generate gem-difluoromethyl radicals their installation onto N-arylmethacrylamides preparation difluorinated oxindole derivatives. To achieve operational simplicity, use readily available benzenethiol as photocatalyst under open-to-air conditions was developed, demonstrating facile multigram targeted fluorinated molecules. Additionally, dispersion-corrected density functional theory (DFT) empirical investigations provide basis support proposed reaction pathway, indicating arene thiolate is efficient organophotocatalyst this transformation.

Language: Английский

Citations

28
Photoredox catalysis harvesting multiple photon or electrochemical energies DOI Creative Commons
Mattia Lepori, Simon Schmid, Joshua P. Barham

et al.

Beilstein Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 19, P. 1055 - 1145

Published: July 28, 2023

Photoredox catalysis (PRC) is a cutting-edge frontier for single electron-transfer (SET) reactions, enabling the generation of reactive intermediates both oxidative and reductive processes via photon activation catalyst. Although this represents significant step towards chemoselective and, more generally, sustainable chemistry, its efficacy limited by energy visible light photons. Nowadays, excellent alternative conditions are available to overcome these limitations, harvesting two different but correlated concepts: use multi-photon such as consecutive photoinduced electron transfer (conPET) combination photo- electrochemistry in synthetic photoelectrochemistry (PEC). Herein, we review most recent contributions fields activations organic functional groups. New opportunities chemists captured, selective reactions employing super-oxidants super-reductants engage unactivated chemical feedstocks, scalability up gram scales continuous flow. This provides comparisons between techniques (multi-photon photoredox PEC) help reader fully understand their similarities, differences potential applications therefore choose which method appropriate given reaction, scale purpose project.

Language: Английский

Citations

27
Visible-Light-Induced Redox-Neutral Difunctionalization of Alkenes and Alkynes DOI
Susmita Mondal, Sumit Ghosh, Alakananda Hajra

et al.

Chemical Communications, Journal Year: 2024, Volume and Issue: 60(72), P. 9659 - 9691

Published: Jan. 1, 2024

The twelve principles of green chemistry illuminate the pathway in direction sustainable and eco-friendly synthesis, marking a fundamental shift synthetic organic paradigms. In this realm, harnessing power visible light for difunctionalization various skeletons without employing any external oxidant or reductant, specifically termed as redox-neutral difunctionalization, has attracted tremendous interest from chemists due to its low cost, easy availability environmentally friendly nature contrast traditional metal-catalyzed difunctionalizations. This review presents an overview recent updates on visible-light-induced reactions with literature coverage up May 2024.

Language: Английский

Citations

12
Organobismuth Compounds as Aryl Radical Precursors via Light-Driven Single-Electron Transfer DOI
Nicholas D. Chiappini, Eric P. Geunes,

Ethan T. Bodak

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(4), P. 2664 - 2670

Published: Feb. 6, 2024

A light-driven method for the generation of aryl radicals from triarylbismuth(III) and (V) reagents is described. Aryl radical proposed to occur through ligand-assisted mesolytic cleavage an organobismuth(IV) intermediate generated either oxidation BiIII or reduction BiV. This mode demonstrated be compatible with a range bimolecular arylations, including hydroarylation electron-deficient olefins arylation diboronates, disulfides, sulfonyl cyanides, phosphites, isocyanides. The intermediacy supported by trapping clock experiments, BiIV–aryl mesolysis computationally.

Language: Английский

Citations

9