Cerium(IV) Carboxylate Photocatalyst for Catalytic Radical Formation from Carboxylic Acids: Decarboxylative Oxygenation of Aliphatic Carboxylic Acids and Lactonization of Aromatic Carboxylic Acids

2020 ◽  
Vol 142 (12) ◽  
pp. 5668-5675 ◽  
Author(s):  
Satoru Shirase ◽  
Sota Tamaki ◽  
Koichi Shinohara ◽  
Keishi Hirosawa ◽  
Hayato Tsurugi ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Radical Formation ◽  
Aromatic Carboxylic Acids ◽  
Aliphatic Carboxylic Acids

scholarly journals Direct deoxygenative borylation of carboxylic acids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jianbin Li ◽  
Chia-Yu Huang ◽  
Mohamad Ataya ◽  
Rustam Z. Khaliullin ◽  
Chao-Jun Li
Keyword(s):  
Carboxylic Acids ◽  
Boronic Acid ◽  
Chemical Space ◽  
Boronic Acids ◽  
Mechanistic Studies ◽  
Sodium Salts ◽  
Aromatic Carboxylic Acids ◽  
Metal Free ◽  
Aliphatic Carboxylic Acids ◽  
Shelf Stable

AbstractCarboxylic acids are readily available, structurally diverse and shelf-stable; therefore, converting them to the isoelectronic boronic acids, which play pivotal roles in different settings, would be highly enabling. In contrast to the well-recognised decarboxylative borylation, the chemical space of carboxylic-to-boronic acid transformation via deoxygenation remains underexplored due to the thermodynamic and kinetic inertness of carboxylic C-O bonds. Herein, we report a deoxygenative borylation reaction of free carboxylic acids or their sodium salts to synthesise alkylboronates under metal-free conditions. Promoted by a uniquely Lewis acidic and strongly reducing diboron reagent, bis(catecholato)diboron (B2cat2), a library of aromatic carboxylic acids are converted to the benzylboronates. By leveraging the same borylative manifold, a facile triboration process with aliphatic carboxylic acids is also realised, diversifying the pool of available 1,1,2-alkyl(trisboronates) that were otherwise difficult to access. Detailed mechanistic studies reveal a stepwise C-O cleavage profile, which could inspire and encourage future endeavours on more appealing reductive functionalisation of oxygenated feedstocks.

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.

Improved QSAR Analysis of the Toxicity of Aliphatic Carboxylic Acids

2003 ◽  
Vol 73 (11) ◽  
pp. 1792-1798 ◽  
Author(s):  
F. P. Maguna ◽  
M. B. Ninez ◽  
N. B. Okulik ◽  
E. A. Castro
Keyword(s):  
Carboxylic Acids ◽  
Qsar Analysis ◽  
Aliphatic Carboxylic Acids
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