Alkylation of 2-methylquinoline with alcohols under additive-free conditions by Al2O3-supported Pt catalyst

Chaudhari, Chandan; Siddiki, S. M. A. Hakim; Shimizu, Ken‐ichi

doi:10.1016/j.tetlet.2013.09.077

Cited by 51 publications

(25 citation statements)

References 22 publications

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“…Note that, unlike the homogeneous Ir‐catalyst reported by Obora, this system does not require additives and excess amounts of 2‐methyl azaarene, but it needs to be performed really at high temperatures. The reusability of Pt/Al 2 O 3 was confirmed by Leaching test studies of 2‐methyl azaarene with benzyl alcohol . The reaction mechanism is similar to the previous report (Scheme ).…”

Section: Alkylationsupporting

confidence: 85%

“…Later Shimizu and his co‐workers reported the same transformation with Al 2 O 3 supported platinum as an alternative catalyst using mesitylene or undecane as the solvent at 170–200 °C for 36 h (Scheme ). Note that, unlike the homogeneous Ir‐catalyst reported by Obora, this system does not require additives and excess amounts of 2‐methyl azaarene, but it needs to be performed really at high temperatures.…”

Section: Alkylationmentioning

confidence: 94%

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C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

Latha

Yaragorla

2020

Eur J Org Chem

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Quinolines and their derivatives have always been promising leads for drug discovery, material applications and designing new catalysts. In the past decade, C(sp 3 )-H functionalization of 2-methyl azaarenes, particularly 2-methyl quinol- [a] ACYLATIONAlmost the early report of C(sp 3 )-H functionalization of 2methyl quinoline was performed by treating with esters using sodamide or potassium amide as the base. This reaction followed the nucleophilic substitution at the sp 2 center of the ester by the benzylic carbanion which was formed by the base treatment (Scheme 2). A total of 15 compounds were made using this method with the yields ranging from 14-62 %. [11] After a couple of years, another report [12] appeared for this transformation, where 2-methyl quinoline and esters were reacted in the presence of phenyllithium to give corresponding acylated quinolines in 36-80 % yields. Later in 1974, J. F. Wolfe reported another approach by treating 2-methyl quinoline with esters refluxed in dimethoxyethane (DME) using sodium hydride for 1-48 h to obtain the corresponding acylated quinolines in 44-98 % yields. [13] Scheme 2. Minireview

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Section: Alkylationsupporting

confidence: 85%

Section: Alkylationmentioning

confidence: 94%

C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

Latha

Yaragorla

2020

Eur J Org Chem

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“…[80] Structure-activity relationship studies have shown that the presence of both the surface Pt 0 species on the Pt metal clusters and the basic support are indispensable.I naf ashion similar to the C sp 3 À H alkylation of methyl-substituted N-heteroarenes by [{Ir(OH)-(cod)} 2 ]/PPh 3 , [68] Pt/Al 2 O 3 catalyzed the alkylation of 2-methylquinoline with alcohols at 170 8 8Cu nder additive-free conditions,t hus affording alkylquinolines in moderate to good yields. [81] b-Alkylation of secondary alcohols with primary alcohols was accomplished by means of a g-alumina-supported silver sub-nanocluster catalyst because of the ability of Ag/g-Al 2 O 3 to facilitate alcohol dehydrogenation. [82] In the presence of the weak base Cs 2 CO 3 ,the ketone products were selectively obtained [Eq.…”

Section: Heterogeneous Transition-metal-catalyzed Calkylation Of Ketomentioning

confidence: 99%

C‐Alkylation of Ketones and Related Compounds by Alcohols: Transition‐Metal‐Catalyzed Dehydrogenation

2015

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Transition-metal-catalyzed C-alkylation of ketones and secondary alcohols, with alcohols, avoids use of organometallic or environmentally unfriendly alkylating agents by means of borrowing hydrogen (BH) or hydrogen autotransfer (HA) activation of the alcohol substrates. Water is formed as the only by-product, thus making the BH process atom-economical and environmentally benign. Diverse homogeneous and heterogeneous transition-metal catalysts, ketones, and alcohols can be used for this transformation, thus rendering the BH process promising for replacing those procedures that use traditional alkylating agents. This Minireview summarizes the advances during the last five years in transition-metal-catalyzed BH α-alkylation of ketones, and β-alkylation of secondary alcohols with alcohols. A discussion on the application of the BH strategy for C-C bond formation is included.

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“…In fact, previously reported iridium-, [33] and ruthenium-, [34] and platinum-catalyzed [35] reactions of methyl-substituted heteroarenes with primary alcohols yielded alkylation products (Scheme 1). On the other hand, to the best of our knowledge,transition-metal-catalyzed ADCs of alcohols and methyl-substituted heteroarenes to form E-disubstituted alkenes with the liberation of hydrogen and water have not been reported thus far.…”

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confidence: 99%

Manganese‐Catalyzed Direct Olefination of Methyl‐Substituted Heteroarenes with Primary Alcohols

2018

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Herein, we present the first catalytic direct olefination of methyl-substituted heteroarenes with primary alcohols through an acceptorless dehydrogenative coupling. The reaction is catalyzed by a complex of the earth-abundant transition metal manganese that is stabilized by a bench-stable NNN pincer ligand derived from 2-hydrazinylpyridine. The reaction is environmentally benign, producing only hydrogen and water as byproducts. A large number of E-disubstituted olefins were selectively obtained with high efficiency.

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Alkylation of 2-methylquinoline with alcohols under additive-free conditions by Al2O3-supported Pt catalyst

Cited by 51 publications

References 22 publications

C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

C‐Alkylation of Ketones and Related Compounds by Alcohols: Transition‐Metal‐Catalyzed Dehydrogenation

Manganese‐Catalyzed Direct Olefination of Methyl‐Substituted Heteroarenes with Primary Alcohols

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Alkylation of 2-methylquinoline with alcohols under additive-free conditions by Al2O3-supported Pt catalyst

Cited by 51 publications

References 22 publications

C(sp3)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

C(sp3)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

C‐Alkylation of Ketones and Related Compounds by Alcohols: Transition‐Metal‐Catalyzed Dehydrogenation

Manganese‐Catalyzed Direct Olefination of Methyl‐Substituted Heteroarenes with Primary Alcohols

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C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds