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Alkylation

About: Alkylation is a research topic. Over the lifetime, 29915 publications have been published within this topic receiving 464944 citations. The topic is also known as: alkylation reaction.


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Journal ArticleDOI
TL;DR: The alkylation of the ortho C-H bonds in benzamides and acrylamides containing an 8-aminoquinoline moiety as a bidentate directing group with unactivated alkyl halides using nickel complexes as catalysts is described, showing high functional group compatibility.
Abstract: The alkylation of the ortho C–H bonds in benzamides and acrylamides containing an 8-aminoquinoline moiety as a bidentate directing group with unactivated alkyl halides using nickel complexes as catalysts is described. The reaction shows high functional group compatibility. In reactions of meta-substituted aromatic amides, the reaction proceeds in a highly selective manner at the less hindered C–H bond.

344 citations

Journal ArticleDOI
TL;DR: 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.
Abstract: 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.

341 citations

Journal ArticleDOI
TL;DR: In this article, a review of catalytic reactions leading to mono-and dialkyl benzenes over zeolites is presented, with an emphasis on the effect of the type of acid sites, zeolite structure, and reaction conditions on the activity and selectivity of these complex reactions.
Abstract: This review describes mechanisms of catalytic reactions leading to mono- and dialkyl benzenes over zeolites, which represent an important part of petrochemical products. The emphasis is given to the effect of the type of acid sites, zeolite structure, and reaction conditions on the activity and selectivity of these complex reactions, and particularly to the individual products with respect to their iso- vs. n- and ortho-, meta-, and para-isomers. The first part of the paper deals with the description and analysis of the structure and properties of the acid sites, and zeolite pore inner structure applied in synthesis of alkyl benzenes. Individual reactions leading to the synthesis of propyl benzene, xylenes, ethyl toluenes, diethyl benzenes, and transformation of trimethyl benzenes to xylenes from the view point of the reaction mechanism, function of the acid sites, and inner pore geometry of zeolites are described in the second part.

340 citations

Journal ArticleDOI
21 Jun 2017-Nature
TL;DR: A polarity-match-based selective sp3 C–H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis is described, which should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry.
Abstract: The functionalization of carbon-hydrogen (C-H) bonds is one of the most attractive strategies for molecular construction in organic chemistry. The hydrogen atom is considered to be an ideal coupling handle, owing to its relative abundance in organic molecules and its availability for functionalization at almost any stage in a synthetic sequence. Although many C-H functionalization reactions involve C(sp3)-C(sp2) coupling, there is a growing demand for C-H alkylation reactions, wherein sp3 C-H bonds are replaced with sp3 C-alkyl groups. Here we describe a polarity-match-based selective sp3 C-H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis. This methodology simultaneously uses three catalytic cycles to achieve hydridic C-H bond abstraction (enabled by polarity matching), alkyl halide oxidative addition, and reductive elimination to enable alkyl-alkyl fragment coupling. The sp3 C-H alkylation is highly selective for the α-C-H of amines, ethers and sulphides, which are commonly found in pharmaceutically relevant architectures. This cross-coupling protocol should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry.

338 citations

Journal ArticleDOI
25 Sep 2015-Science
TL;DR: The studies indicate a particular role of tetra-n-butylammonium phosphate in enhancing the selectivity for α C-H bonds in alcohols in the presence of allylic, benzylic, α-C=O, and α-ether C–H bonds.
Abstract: The efficiency and selectivity of hydrogen atom transfer from organic molecules are often difficult to control in the presence of multiple potential hydrogen atom donors and acceptors. Here, we describe the mechanistic evaluation of a mode of catalytic activation that accomplishes the highly selective photoredox α-alkylation/lactonization of alcohols with methyl acrylate via a hydrogen atom transfer mechanism. Our studies indicate a particular role of tetra-n-butylammonium phosphate in enhancing the selectivity for α C–H bonds in alcohols in the presence of allylic, benzylic, α-C=O, and α-ether C–H bonds.

337 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023652
20221,161
2021561
2020516
2019630
2018631