Simple and Clean Photo-induced Methylation of Heteroarenes with MeOH

Liu, Wenbo; Yang, Xiaobo; Zhou, Zhong‐Zhen; Li, Chao‐Jun

doi:10.1016/j.chempr.2017.03.009

Cited by 175 publications

(101 citation statements)

References 62 publications

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“…Other reagents have indeed been exploited for the selective alkylation of CÀHb onds in electron-deficient heteroarenes:t hey include alcohols, [70][71][72][73] carboxylic acids, [74][75][76][77][78][79][80][81][82][83] peroxides, [84,85] aldehydes, [86][87][88] acyl chlorides, [89] as well as some less common reagents such as pyridinium salts, [90] dihydropyridines, [91] N-tosylhydrazones, [92] N-(acyloxy)phthalimides, [93,94] a-diazocarbonyl derivatives, [95] a-carbonyl alkylsulfones, [96] carboxylic xanthates, [97,98] cycloalkanols, [99,100] and Wittig reagents. [101] Theu se of alcohols as remarkably attractive alkylating agents was elegantly exploited by MacMillan in 2015 for the direct alkylation of pyridine derivatives by using as trategy that combines photoredox catalysis and hydrogen atom transfer catalysis.…”

Section: Alkylation With Other Reagentsmentioning

confidence: 99%

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

2019

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The alkylation of arenes is one of the most fundamental transformations in chemical synthesis leading to privileged scaffolds in many areas of science. Classical methods for the introduction of alkyl groups to arenes are mostly based on the Friedel-Crafts reaction, radical additions, metallation or pre-functionalization of the arene: these methods however suffer from limitations in scope, efficiency and selectivity. Moreover, they are based on the innate reactivity of the starting arene, favoring the alkylation at a certain position and rendering the introduction of alkyl chains at other positions much more challenging. This can be addressed by the use of a directing group facilitating, in the presence of a metal catalyst, the regioselective alkylation of a C-H bond. These directed alkylations of C-H bonds in arenes are overviewed, in a comprehensive manner, in this review article.

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Section: Alkylation With Other Reagentsmentioning

confidence: 99%

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

2019

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“…The authors also outlined the limitations of the method, for instance, 78 was not formed from the corresponding nicotine under the conditions (Table 6). [44] Similarly,B arriault and coworkers describedaphotochemical alkylation and reduction of quinolines, pyridines,a nd phenanthridines.I nstead of TFA, HCl was used as the additive fort he protonation of substrates. As ac omparison, 72(b)w as obtained in 80 %y ield.…”

Section: Methanol In Metal-free Photoinducedreactionsmentioning

confidence: 99%

Recent Advances in Methylation: A Guide for Selecting Methylation Reagents

Chen

2018

Chemistry A European J

186

121

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Methylation is a well‐known structural modification in organic and medicinal chemistry. This review summarizes recent advances in methylation by categorizing specific methylation reagents. The challenges of mono N‐methylation of aliphatic amines and N‐methylation of peptides are discussed. This review will be useful for chemists wanting to select the appropriate reagents for methylation chemistry. Based on the large diversity of methylation reagents and their wide scope, this review also broadens perspectives on which strategies to select for utilizing a particular methylation, resulting in an increased flexibility in synthetic route planning.

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“…Auch andere Reagenzien wurden fürd ie selektive Alkylierung von C-H-Bindungen in elektronenarmen Heteroarenen genutzt:H ierzu zählen Alkohole, [70][71][72][73] Carbonsäuren, [74][75][76][77][78][79][80][81][82][83] Peroxide, [84,85] Aldehyde, [86][87][88] Acylchloride [89] sowie…”

Section: Alkylierung Mit Anderen Reagenzienunclassified

Jenseits von Friedel und Crafts: dirigierte Alkylierung von C‐H‐Bindungen in Arenen

Evano

Theunissen

2019

Angewandte Chemie

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Die Alkylierung von Arenen ist eine der grundlegendsten Transformationen in der chemischen Synthese und führt in vielen wissenschaftlichen Bereichen zu privilegierten Molekülgerüsten. Klassische Methoden für die Einführung von Alkylgruppen in Arene beruhen zumeist auf der Friedel‐Crafts‐Reaktion, Radikaladditionen, Metallierungen oder Präfunktionalisierungen von Arenen; die Anwendungsbreite, Effizienz und Selektivität dieser Methoden sind jedoch begrenzt. Außerdem bauen sie auf der inhärenten Reaktivität des Ausgangsarens auf, die die Alkylierung in einer bestimmten Position bevorzugt und die Einführung von Alkylketten an anderen Stellen wesentlich schwieriger macht. Dieses Problem kann durch die Verwendung einer dirigierenden Gruppe angegangen werden, die in Gegenwart eines Metallkatalysators die regioselektive Alkylierung einer C‐H‐Bindung vereinfacht. Diese dirigierten Alkylierungen von C‐H‐Bindungen in Arenen werden im vorliegenden Aufsatz zusammengefasst.

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Simple and Clean Photo-induced Methylation of Heteroarenes with MeOH

Cited by 175 publications

References 62 publications

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

Beyond Friedel and Crafts: Directed Alkylation of C−H Bonds in Arenes

Recent Advances in Methylation: A Guide for Selecting Methylation Reagents

Jenseits von Friedel und Crafts: dirigierte Alkylierung von C‐H‐Bindungen in Arenen

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