scholarly journals Acyl Radicals from Aromatic Carboxylic Acids by Means of Visible-Light Photoredox Catalysis

2015 ◽  
Vol 127 (47) ◽  
pp. 14272-14275 ◽  
Author(s):  
Giulia Bergonzini ◽  
Carlo Cassani ◽  
Carl-Johan Wallentin
Keyword(s):  
Visible Light ◽  
Carboxylic Acids ◽  
Photoredox Catalysis ◽  
Aromatic Carboxylic Acids ◽  
Acyl Radicals

scholarly journals Acyl Radical Chemistry via Visible-Light Photoredox Catalysis

Synthesis ◽  
2018 ◽  
Vol 51 (02) ◽  
pp. 303-333 ◽  
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

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

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.

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

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.

Room temperature decarboxylative trifluoromethylation of α,β-unsaturated carboxylic acids by photoredox catalysis

2014 ◽  
Vol 50 (18) ◽  
pp. 2308-2310 ◽  
Author(s):  
Pan Xu ◽  
Ablimit Abdukader ◽  
Kaidong Hu ◽  
Yixiang Cheng ◽  
Chengjian Zhu
Keyword(s):  
Visible Light ◽  
Carboxylic Acids ◽  
Room Temperature ◽  
Photoredox Catalysis ◽  
Unsaturated Carboxylic Acids

A visible-light-induced decarboxylative trifluoromethylation of α,β-unsaturated carboxylic acids, which uses the Togni reagent as the CF3 source is disclosed.

Metal-Free Regioselective Alkylation of Imidazo[1,2-a]pyridines with N-Hydroxyphthalimide Esters under Organic Photoredox Catalysis

Synlett ◽  
2020 ◽  
Vol 31 (04) ◽  
pp. 363-368 ◽  
Author(s):  
Can Jin ◽  
Bin Sun ◽  
Tengwei Xu ◽  
Liang Zhang ◽  
Rui Zhu ◽  
...  
Keyword(s):  
Visible Light ◽  
Carboxylic Acids ◽  
Room Temperature ◽  
Eosin Y ◽  
Photoredox Catalysis ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Regioselective Alkylation ◽  
Decarboxylative Coupling ◽  
Aliphatic Carboxylic Acids

A visible-light-induced direct C–H alkylation of imidazo[1,2-a]pyridines has been developed. It proceeds at room temperature by employing inexpensive Eosin Y as a photocatalyst and alkyl N-hydroxyphthalimide (NHP) esters as alkylation reagents. A variety of NHP esters derived from aliphatic carboxylic acids (primary, secondary, and tertiary) were tolerated in this protocol, giving the corresponding C-5-alkylated products in moderate to excellent yields. Mechanistic studies indicate that a radical decarboxylative coupling pathway was involved in this process.

Decarboxylative Alkynylation and Carbonylative Alkynylation of Carboxylic Acids Enabled by Visible-Light Photoredox Catalysis

2015 ◽  
Vol 54 (38) ◽  
pp. 11196-11199 ◽  
Author(s):  
Quan-Quan Zhou ◽  
Wei Guo ◽  
Wei Ding ◽  
Xiong Wu ◽  
Xi Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Carboxylic Acids ◽  
Photoredox Catalysis

scholarly journals Mild, visible light-mediated decarboxylation of aryl carboxylic acids to access aryl radicals

2017 ◽  
Vol 8 (5) ◽  
pp. 3618-3622 ◽  
Author(s):  
L. Candish ◽  
M. Freitag ◽  
T. Gensch ◽  
F. Glorius
Keyword(s):  
Visible Light ◽  
Carboxylic Acids ◽  
Radical Formation ◽  
Photoredox Catalysis ◽  
Aryl Radical ◽  
Aryl Radicals

Herein we present the first example of aryl radical formation via the visible light-mediated decarboxylation of aryl carboxylic acids using photoredox catalysis.

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