Recent progress in cathodic reduction-enabled organic electrosynthesis: Trends, challenges, and opportunities DOI Creative Commons
Binbin Huang, Zemin Sun, Genban Sun

et al.

eScience, Journal Year: 2022, Volume and Issue: 2(3), P. 243 - 277

Published: April 23, 2022

Compared with general redox chemistry, electrochemistry using the electron as a potent, controllable, yet traceless alternative to chemical oxidants/reductants usually offers more sustainable options for achieving selective organic synthesis. With its environmentally benign features gradually being uncovered and studied, electrosynthesis is currently undergoing revival becoming rapidly growing area within synthetic community. Among electrochemical transformations, anodically enabled ones have been far extensively exploited than those driven by cathodic reduction, although both approaches are conceptually attractive. To stimulate development of cathodically reactions, this review summarizes recently developed reductive electrosynthetic protocols, discussing highlighting reaction features, substrate scopes, applications, plausible mechanisms reveal recent trends in area. Herein, reduction-enabled preparative transformations categorized into four types: reduction (1) unsaturated hydrocarbons, (2) heteroatom-containing carbon-based systems, (3) saturated C-hetero or C–C polar/strained bonds, (4) hetero-hetero linkages. Apart from net electroreductive few examples photo-electrosynthesis well paired electrolysis also introduced, which offer opportunities overcome certain limitations improve versatility. The electrochemically driven, transition metal-catalyzed cross-couplings that comprehensively discussed several other reviews not included here.

Language: Английский

Visible-Light-Driven Reductive Carboarylation of Styrenes with CO2 and Aryl Halides DOI
Hao Wang, Yuzhen Gao,

Chunlin Zhou

et al.

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(18), P. 8122 - 8129

Published: April 20, 2020

The first example of visible-light-driven reductive carboarylation styrenes with CO2 and aryl halides in a regioselective manner has been achieved. A broad range iodides bromides were compatible this reaction. Moreover, pyridyl halides, alkyl even chlorides also viable method. These findings may stimulate the exploration novel Meerwein arylation-addition reactions user-friendly as radical sources photocatalytic utilization CO2.

Language: Английский

Citations

230
A Rational Approach to Organo‐Photocatalysis: Novel Designs and Structure‐Property Relationships DOI
Alberto Vega‐Peñaloza, Javier Mateos, Xavier Companyó

et al.

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(3), P. 1082 - 1097

Published: June 22, 2020

Organic photocatalysts are emerging as viable and more sustainable tools than metal complexes. Recently, the field of organo-photocatalysis has experienced an explosion in terms applications, redesign well-established systems, identification novel scaffolds. A rational approach to structural modification different is key accessing unprecedented reactivity, while improving their catalytic performances. We herein discuss concepts underpinning scaffold some most recently used analyze how specific changes alter physicochemical redox properties.

Language: Английский

Citations

210
Non-innocent Radical Ion Intermediates in Photoredox Catalysis: Parallel Reduction Modes Enable Coupling of Diverse Aryl Chlorides DOI
Alyah F. Chmiel, Oliver P. Williams, Colleen P. Chernowsky

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(29), P. 10882 - 10889

Published: July 13, 2021

We describe a photocatalytic system that elicits potent photoreductant activity from conventional photocatalysts by leveraging radical anion intermediates generated in situ. The combination of an isophthalonitrile photocatalyst and sodium formate promotes diverse aryl coupling reactions abundant but difficult to reduce chloride substrates. Mechanistic studies reveal two parallel pathways for substrate reduction both enabled key terminal reductant byproduct, carbon dioxide anion.

Language: Английский

Citations

204
Radical Chain Reduction via Carbon Dioxide Radical Anion (CO2•–) DOI
Cecilia M. Hendy,

Gavin C. Smith,

Zihao Xu

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(24), P. 8987 - 8992

Published: June 9, 2021

We developed an effective method for reductive radical formation that utilizes the anion of carbon dioxide (CO2•–) as a powerful single electron reductant. Through polarity matched hydrogen atom transfer (HAT) between electrophilic and formate salt, CO2•– occurs key element in new chain reaction. Here, initiation can be performed through photochemical or thermal means, we illustrate ability this approach to accomplish activation range substrate classes. Specifically, employed strategy intermolecular hydroarylation unactivated alkenes with (hetero)aryl chlorides/bromides, deamination arylammonium salts, aliphatic ketyl formation, sulfonamide cleavage. show reactivity electron-poor olefins results either reduction alkene hydrocarboxylation, where potentials utilized predict reaction outcome.

Language: Английский

Citations

194
Organocatalyzed Birch Reduction Driven by Visible Light DOI
Justin P. Cole, Dian‐Feng Chen, Max Kudisch

et al.

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(31), P. 13573 - 13581

Published: July 14, 2020

The Birch reduction is a powerful synthetic methodology that uses solvated electrons to convert inert arenes 1,4-cyclohexadienes-valuable intermediates for building molecular complexity. reductions traditionally employ alkali metals dissolved in ammonia produce electron the of unactivated such as benzene (

Language: Английский

Citations

191
Electrophotocatalysis: Combining Light and Electricity to Catalyze Reactions DOI
He Huang, Keri A. Steiniger, Tristan H. Lambert

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(28), P. 12567 - 12583

Published: July 11, 2022

Visible-light photocatalysis and electrocatalysis are two powerful strategies for the promotion of chemical reactions that have received tremendous attention in recent years. In contrast, processes combine these modalities, an area termed electrophotocatalysis, until recently remained quite rare. However, over past several years a number reports this shown potential combining power light electrical energy to realize new catalytic transformations. Electrophotocatalysis offers ability perform photoredox without need large quantities stoichiometric or superstoichiometric oxidants reductants by making use electrochemical as electron source sink. addition, electrophotocatalysis is readily amenable generation open-shell photocatalysts, which tend exceptionally strong redox potentials. way, potent yet selective been realized under relatively mild conditions. This Perspective highlights advances provides some possible avenues future work growing area.

Language: Английский

Citations

188
Unveiling Extreme Photoreduction Potentials of Donor–Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides DOI
Jinhui Xu,

Jilei Cao,

Xiangyang Wu

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(33), P. 13266 - 13273

Published: Aug. 16, 2021

Since the seminal work of Zhang in 2016, donor–acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied photoredox catalysis and used excellent metal-free alternatives to noble metal Ir- Ru-based photocatalysts. However, all reported reactions involving this chromophore family are based on harnessing energy from a single visible light photon, with limited range redox potentials −1.92 +1.79 V vs SCE. Here, we document unprecedented discovery that fluorophores can undergo consecutive photoinduced electron transfer (ConPET) achieve very high reduction potentials. One newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN•–*, which be activate reductively recalcitrant aryl chlorides (Ered ≈ −1.9 −2.9 SCE) under mild conditions. The resultant radicals engaged synthetically valuable aromatic C–B, C–P, C–C bond formation furnish arylboronates, arylphosphonium salts, arylphosphonates, spirocyclic cyclohexadienes.

Language: Английский

Citations

187
Photocatalytic strategies for the activation of organic chlorides DOI
Martyna Cybularczyk‐Cecotka,

Joanna Szczepanik,

Maciej Giedyk

et al.

Nature Catalysis, Journal Year: 2020, Volume and Issue: 3(11), P. 872 - 886

Published: Nov. 12, 2020

Language: Английский

Citations

175
Contemporary methods for generation of aryl radicals DOI

Nikita Kvasovs,

Vladimir Gevorgyan

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 50(4), P. 2244 - 2259

Published: Dec. 14, 2020

The synthetic utility of aryl radicals has been established in the last century, however, their broad applications were hampered by ineffective generation methods. It was decade, that a rapid development various redox systems took place, thus triggering renaissance radical chemistry. This tutorial review focuses on start-of-the-art methods for radicals. Primarily, light-induced systems, including photoredox catalysis, visible light transition metal and chemistry electron donor-acceptor complexes, are reviewed. main current precursors evaluated together with selected examples modern applications.

Language: Английский

Citations

162
Electrochemical generation of nitrogen-centered radicals for organic synthesis DOI Creative Commons
Na Chen, Hai‐Chao Xu

Green Synthesis and Catalysis, Journal Year: 2021, Volume and Issue: 2(2), P. 165 - 178

Published: March 29, 2021

There is a resurgence of interests in organic electrochemistry, which generally accepted as green synthetic tool. In this context, many electrochemical methods have been developed the past decade to access various nitrogen-centered radicals (NCRs) from readily available precursors controlled fashion, enabling rapid development NCR-mediated new reactions for construction nitrogen-containing compounds. review, recent advances chemistry electrochemically generated NCRs are critically highlighted, based on strategies their formation and types NCRs. Focus put mechanism generation different applications.

Language: Английский

Citations

161