N-Heterocyclic carbene catalysed aerobic oxidation of aromatic aldehydes to aryl esters using boronic acids

Arde, Panjab; Ramanjaneyulu, Bandaru T.; Reddy, Virsinha; Saxena, Apurv; Anand, Ramasamy Vijaya

doi:10.1039/c1ob06566a

Cited by 48 publications

(22 citation statements)

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“…[17] Carboxylic acids can be coupled with arylboronic acids or silanes in copper-mediated reactions at elevated temperature. [18,19] Aryl esters can also be synthesized from carboxylic acids and phenols by iron-catalyzed oxidative activation. [20] Pd-catalyzed oxidative coupling of phenols with aromatic aldehydes or benzylic alcohols [21] or carbonylative coupling with aryl halides also deliver aryl esters.…”

Section: Introductionmentioning

confidence: 99%

Metal‐Free Arylation of Oxygen Nucleophiles with Diaryliodonium Salts

Jalalian

Petersen

Olofsson

2012

Chemistry A European J

152

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Phenols and carboxylic acids are efficiently arylated with diaryliodonium salts. The reaction conditions are mild, metal free, and avoid the use of halogenated solvents, additives, and excess reagents. The products are obtained in good-to-excellent yields after short reaction times. Steric hindrance is very well tolerated, both in the nucleophile and diaryliodonium salt. The scope includes ortho- and halo-substituted products, which are difficult to obtain by metal-catalyzed protocols. Many functional groups are tolerated, including carbonyl groups, heteroatoms, and alkenes. Unsymmetric salts can be chemoselectively utilized to obtain products with hitherto unreported levels of steric congestion. The arylation has been extended to sulfonic acids, which can be converted to sulfonate esters by two different approaches. With recent advances in efficient synthetic procedures for diaryliodonium salts the reagents are now inexpensive and readily available. The iodoarene byproduct formed from the iodonium reagent can be recovered quantitatively and used to regenerate the diaryliodonium salt, which improves the atom economy.

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Section: Introductionmentioning

confidence: 99%

Metal‐Free Arylation of Oxygen Nucleophiles with Diaryliodonium Salts

Jalalian

Petersen

Olofsson

2012

Chemistry A European J

152

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“…Beispielsweise gelang es Arnand und Mitarbeitern, Arylester aus Boronsäuren zu erzeugen (Schema 15). [34] Dies war die Abwandlung einer früheren Entdeckung von Gois und Mitarbeitern, die einen Eisen-NHC-Komplex verwendeten, um dieselbe Umwandlung zu realisieren. [35] Chen gelang es,d ie gleichen Produkte (Arylester) durch eine oxidative Palladium/NHC-Veresterung von Aldehyden und Phenolen zugänglich zu machen.…”

Section: Oxidative Nhc-katalyseunclassified

Kooperative Katalyse mit N‐heterocyclischen Carbenen

2016

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Die Katalyse mit N‐heterocyclischen Carbenen (NHC) hat sich in der organischen Synthese zu einer leistungsfähigen Strategie entwickelt, um komplexe Moleküle hauptsächlich durch Umpolungsverfahren aufzubauen. Diese einzigartigen Lewis‐Basen wurden verwendet, um Acylanionen, Enolate und Homoenolate katalytisch zu generieren. Kürzlich wurde eine neue Strategie entwickelt, mit der die Anwendbarkeit der Carbenkatalyse bei Synthesen durch den wirksamen Einsatz zusätzlicher Aktivierungsarten erheblich erweitert werden konnte: die kooperative Katalyse. Durch die sorgfältige Auswahl von Cokatalysatoren können Reaktivitäten, Ausbeuten und Stereoselektivitäten verbessert werden. In einigen Fällen haben diese katalytischen Additive die Regioselektivität oder Diastereoselektivität verändert. In diesem Kurzaufsatz werden die neuesten Fortschritte bei der kooperativen Katalyse mit NHCs herausgestellt und die Gesamtentwicklung des Gebiets betrachtet.

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“…Recently, we developed an efficient organocatalytic route for the direct conversion of aromatic aldehydes into aryl esters by using aryl boronic acids under oxidative NHC‐catalyzed conditions 14. Although aryl esters were obtained in excellent yields, this method did not allow us to access aliphatic esters because aliphatic boronic acids did not react with the aldehydes under the optimized reaction conditions.…”

Section: Introductionmentioning

confidence: 99%