Products and kinetics of decarboxylation of activated and unactivated aromatic cuprous carboxylates in pyridine and in quinoline

Cohen, Theodore; Berninger, Ronald W.; Wood, John T.

doi:10.1021/jo00399a010

Cited by 77 publications

(50 citation statements)

References 22 publications

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“…We established that the decarboxylation reactions of these compounds proceeded most effectively witb copper oxide in quinoline and Nmethylpyrrolidinone. The researches of Cohen and his associates were extremely helpful in the selection and modXcation of this procedure [5]. When this procedure was applied to the oxidation products of the Pocahontas No.…”

Section: Resultsmentioning

confidence: 99%

Chemical constitution of Pocahontas No. 3 coal

Stock¹,

Obeng²

1993

Energy Fuels

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A new method for the definition of the larger aromatic structural elements in high-rank coals has been developed. The procedure involves the oxidative decomposition of the coal with oxygen in basic solution and the subsequent decarboxylation of the aromatic carboxylic acids to yield a mixture of aromatic compounds that can readily be analyzed by conventional methods. This approach has been tested with pure compounds and applied to Pocahontas No. 3 coal.

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Section: Resultsmentioning

confidence: 99%

Chemical constitution of Pocahontas No. 3 coal

Stock¹,

Obeng²

1993

Energy Fuels

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“…The copper source had a very limited influence on the reaction outcome (entry 14). Interestingly, PA C H T U N G T R E N N U N G (p-Tol) 3 , the most effective ligand under thermal conditions (entry 1), was now clearly inferior to Tol-BINAP (entries 13,15). Under the best conditions, the reaction time could be reduced even further to 2.5 min, and a yield of 81 % was achieved (entry 16).…”

Section: Entrymentioning

confidence: 99%

“…[14] It maintains the advantage presented by traditional cross-couplings of being able to predefine the position of carbonÀcarbon bond formation by leaving groups, while obviating the need for stoichiometric organometallic reagents. Based on elemental steps also found in the pioneering work on decarboxylation reactions by Cohen, [15] Nilsson, [16] and Myers, [17] we propose a reaction principle as illustrated in Scheme 2.…”

Section: Introductionmentioning

confidence: 99%

Biaryl and Aryl Ketone Synthesis via Pd‐Catalyzed Decarboxylative Coupling of Carboxylate Salts with Aryl Triflates

Gooßen

Linder

Rodríguez

et al. 2009

Chemistry A European J

128

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A bimetallic catalyst system has been developed that for the first time allows the decarboxylative cross-coupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non-coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic cross-coupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho-substituted or otherwise activated derivatives to a broad range of ortho-, meta-, and para-substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of Cu(I)/1,10-phenanthroline (10-15 mol %) and PdI(2)/phosphine (2-3 mol %) in NMP for 1-24 h, the other involving Cu(I)/1,10-phenanthroline (6-15 mol %) and PdBr(2)/Tol-BINAP (2 mol %) in NMP using microwave heating for 5-10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non-activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylative cross-couplings are discussed.

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“…While the exact mechanism remained the subject of discussion, experimental data revealed that the protodecarboxylation is almost unaffected by the copper source employed, but strongly facilitated by the presence of bipyridine ligands at the copper and the use of aromatic amines as solvents. [6] Stoichiometric copper-mediated decarboxylation reactions were subsequently described for a considerable range of benzoic acids, demonstrating the preparative use of the reaction in organic synthesis. [7] However, significant drawbacks remained: most importantly, the arenecarboxylic acids had to either be ortho-substituted with electron-withdrawing groups such as nitro or halo, or to contain a heteroatom in order to undergo decarboxylation with reasonable yields.…”

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confidence: 99%