Aroyl chlorides as novel acyl radical precursors via visible-light photoredox catalysis

Visible light and photoredox catalysis have emerged as a powerful and long-lasting tool for organic synthesis, demonstrating the importance of a variety of chemical bond formation methods. Natural products, physiologically...

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The chemistry of amine radical cations produced by visible light photoredox catalysis

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.9.234 ◽

2013 ◽

Vol 9 ◽

pp. 1977-2001 ◽

Cited By ~ 238

Author(s):

Jie Hu ◽

Jiang Wang ◽

Theresa H Nguyen ◽

Nan Zheng

Keyword(s):

Visible Light ◽

Radical Cations ◽

Reactive Intermediates ◽

Visible Light Photocatalysis ◽

Photoredox Catalysis ◽

Iminium Ions ◽

Distonic Ions ◽

Synthetic Intermediates

Amine radical cations are highly useful reactive intermediates in amine synthesis. They have displayed several modes of reactivity leading to some highly sought-after synthetic intermediates including iminium ions, α-amino radicals, and distonic ions. One appealing method to access amine radical cations is through one-electron oxidation of the corresponding amines under visible light photoredox conditions. This approach and subsequent chemistries are emerging as a powerful tool in amine synthesis. This article reviews synthetic applications of amine radical cations produced by visible light photocatalysis.

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Excited radical anions and excited anions in visible light photoredox catalysis

Physical Sciences Reviews ◽

10.1515/psr-2017-0185 ◽

2019 ◽

Vol 4 (12) ◽

Cited By ~ 1

Author(s):

Indrajit Ghosh

Keyword(s):

Visible Light ◽

Organic Synthesis ◽

Transition Metal Complexes ◽

Organic Dyes ◽

Visible Light Photocatalysis ◽

Radical Anions ◽

Photoredox Catalysis ◽

Inorganic Semiconductors ◽

Redox Active ◽

Excited Radical

Abstract Over the last decade, visible light photocatalysis has dramatically increased the arsenal of methods for organic synthesis and changed the way we activate molecules for chemical reactions. Polypyridyl transition metal complexes, redox-active organic dyes, and inorganic semiconductors are typically used as photocatalysts for such transformations. This chapter reviews the applications of radical anions and anions as photosensitizers in visible light photoredox catalysis.

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An amorphous/crystalline g-C3N4 homojunction for visible light photocatalysis reactions with superior activity

Chemical Communications ◽

10.1039/c8cc01824c ◽

2018 ◽

Vol 54 (37) ◽

pp. 4720-4723 ◽

Cited By ~ 45

Author(s):

Zhiguo Liu ◽

Gang Wang ◽

Hsueh-Shih Chen ◽

Ping Yang

Keyword(s):

High Temperature ◽

Visible Light ◽

Visible Light Photocatalysis ◽

First Time

An amorphous/crystalline g-C3N4 homojunction was prepared for the first time at high temperature, in which the ratio of crystalline g-C3N4 in the homojunction was optimized.

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Visible-light photoredox catalyzed hydroacylation of electron-deficient alkenes: carboxylic anhydride as an acyl radical source

Organic Chemistry Frontiers ◽

10.1039/c7qo00453b ◽

2017 ◽

Vol 4 (11) ◽

pp. 2230-2234 ◽

Cited By ~ 16

Author(s):

Shupeng Dong ◽

Guibing Wu ◽

Xiaoqian Yuan ◽

Chuncheng Zou ◽

Jinxing Ye

Keyword(s):

Visible Light ◽

Michael Addition ◽

Photoredox Catalysis ◽

Acyl Radical

Simple aromatic carboxylic anhydrides have been employed for a novel acyl Michael addition via visible light photoredox catalysis.

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Cascade cyclization reactions of alkylidenecyclopropanes for the construction of polycyclic lactams and lactones by visible light photoredox catalysis

Organic Chemistry Frontiers ◽

10.1039/c9qo01360a ◽

2020 ◽

Vol 7 (2) ◽

pp. 374-379 ◽

Cited By ~ 2

Author(s):

Mintao Chen ◽

Yin Wei ◽

Min Shi

Keyword(s):

Visible Light ◽

Membered Ring ◽

Visible Light Photocatalysis ◽

Photoredox Catalysis ◽

Cyclization Reactions ◽

Cascade Cyclization

A facile method for the synthesis of seven- and eight-membered ring-containing polycyclic lactams and lactones by visible light photocatalysis has been developed.

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Alkenylation of unactivated alkyl bromides through visible light photocatalysis

Chemical Communications ◽

10.1039/c8cc08362b ◽

2019 ◽

Vol 55 (1) ◽

pp. 107-110 ◽

Cited By ~ 18

Author(s):

Quan-Quan Zhou ◽

Simon Josef Siegfried Düsel ◽

Liang-Qiu Lu ◽

Burkhard König ◽

Wen-Jing Xiao

Keyword(s):

Visible Light ◽

Visible Light Photocatalysis ◽

Atom Transfer ◽

Alkyl Bromides ◽

Visible Light Driven ◽

First Time

Two visible-light driven alkenylation reactions of unactivated alkyl bromides, which were enabled by the use of Ir(dF(CF3)ppy)2(dtbbpy)PF6 as the photocatalyst and (TMS)3SiH as the atom transfer reagent to activate the alkyl bromides, were described for the first time.

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Acyl Radical Chemistry via Visible-Light Photoredox Catalysis

Synthesis ◽

10.1055/s-0037-1610329 ◽

2018 ◽

Vol 51 (02) ◽

pp. 303-333 ◽

Cited By ~ 57

Author(s):

Ming-Yu Ngai ◽

Arghya Banerjee ◽

Zhen Lei

Keyword(s):

Visible Light ◽

Carboxylic Acids ◽

Easy Access ◽

Hypervalent Iodine ◽

Photoredox Catalysis ◽

Acyl Radical ◽

Diverse Range ◽

Acyl Chlorides ◽

Keto Acids ◽

Acyl Radicals

Visible-light photoredox catalysis enables easy access to acyl radicals under mild reaction conditions. Reactive acyl radicals, generated from various acyl precursors such as aldehydes, α-keto acids, carboxylic acids, anhydrides, acyl thioesters, acyl chlorides, or acyl silanes, can undergo a diverse range of synthetically useful transformations, which were previously difficult or inaccessible. This review summarizes the recent progress on visible-light-driven acyl radical generation using transition-metal photoredox catalysts, metallaphotocatalysts, hypervalent iodine catalysts or organic photocatalysts.1 Introduction2 The Scope of This Review3 Aldehydes as a Source of Acyl Radicals4 α-Keto Acids as a Source of Acyl Radicals5 Carboxylic Acids as a Source of Acyl Radicals6 Anhydrides as a Source of Acyl Radicals7 Acyl Thioesters as a Source of Acyl Radicals8 Acyl Chlorides as a Source of Acyl Radicals9 Acyl Silanes as a Source of Acyl Radicals10 Conclusions and Future Outlook

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Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage–Independent Activation of Strong C–O Bonds

10.26434/chemrxiv.6349253 ◽

2018 ◽

Author(s):

Erin Stache ◽

Alyssa B. Ertel ◽

Tomislav Rovis ◽

Abigail G. Doyle

Keyword(s):

Carboxylic Acids ◽

Functional Groups ◽

Single Step ◽

Direct Access ◽

Photoredox Catalysis ◽

Acyl Radical ◽

Synthetic Strategy ◽

Acyl Radicals ◽

Benzyl Radicals ◽

Aliphatic Carboxylic Acids

Alcohols and carboxylic acids are ubiquitous functional groups found in organic molecules that could serve as radical precursors, but C–O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen centered nucleophile. We first show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H-atom trapping to afford the deoxygenated product. Using the same method, we demonstrate access to synthetically versatile acyl radicals which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge new C–O, C–N and C–C bonds in a single step.

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Regioselective C3-H Trifluoromethylation of 2H-Indazole Under Transition-Metal-Free Photoredox Catalysis

10.26434/chemrxiv.7796603.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Arumugavel Murugan ◽

Venkata Nagarjuna Babu ◽

Nagaraj Sabarinathan ◽

Sharada Duddu. S

Keyword(s):

Transition Metal ◽

Visible Light ◽

Practical Approach ◽

Hypervalent Iodine ◽

Radical Mechanism ◽

Photoredox Catalysis ◽

Metal Free

Here we report a visible-light-promoted metal-free regioselective C3-H trifluoromehtylation reaction that proceeds via radical mechanism and which supported by control experiments. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the present trifluoromethylation reaction and synthesis of a library of trifluoromethylated indazoles.

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