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.

Ir(I)-catalyzed C-H bond alkylation of C2-position of indole with alkenes: selective synthesis of linear or branched 2-alkylindoles.

Abstract: A cationic iridium-catalyzed C2-alkylation of N-substituted indole derivatives with various alkenes has been developed, which selectively gives linear or branched 2-alkylindoles in high to excellent selectivity. This protocol relies on the use of the carbonyl group on the nitrogen atom of indole as a directing group: a linear product was predominant when an acetyl group was used as a directing group, and a branched product was predominant with a benzoyl group.

Toward "Willowlike" Thermotropic Dendrimers

Abstract: The synthesis and characterization of the AB 2 monomers 6-bromo-1-(4-hydroxy-4'-biphenylyl)-2-(4-hydroxyphenyl)hexane (8 or TPH-b), 13-bromo-1-(4-hydroxyphenyl)-2-[4-(6-hydroxy-2-naphthalenylyl)-phenyl]tridecane (22 or BPNT-b), and 13-bromo-1-(4-hydroxyphenyl)-2-(4-hydroxy-4''-p-terphenylyl)tridecane (30 or TPT-b) are described. The phase-transfer-catalyzed polyetherification of all monomers followed by in situ alkylation of their phenolate chain ends with bromoalkanes, benzyl chloride, or allyl chloride led to the soluble hyperbranched polymers TPH-b-X, BPNT-b-X, and TPT-b-X (where X refers to the nature of their chain ends, for example, when X= Bz= benzyl, X= All= allyl, and, when X= numeral, it represents the number of carbons in the alkyl chain end)

General and Mild Cobalt-Catalyzed C-Alkylation of Unactivated Amides and Esters with Alcohols.

Abstract: The borrowing hydrogen or hydrogen autotransfer methodology is an elegant and sustainable or green concept to construct carbon–carbon bonds. In this concept, alcohols, which can be obtained from barely used and indigestible biomass, such as lignocellulose, are employed as alkylating reagents. An especially challenging alkylation is that of unactivated esters and amides. Only noble metal catalysts based on iridium and ruthenium have been used to accomplish these reactions. Herein, we report on the first base metal-catalyzed α-alkylation of unactivated amides and esters by alcohols. Cobalt complexes stabilized with pincer ligands, recently developed in our laboratory, catalyze these reactions very efficiently. The precatalysts can be synthesized easily from commercially available starting materials on a multigram scale and are self-activating under the basic reaction conditions. This Co catalyst class is also able to mediate alkylation reactions of both esters and amides. In addition, we apply the methodolo...

Catalysis of Friedel‐Crafts Alkylation by a Montmorillonite Doped with Transition‐Metal Cations

Abstract: Catalysts are obtained by exchange of the interstitial cations in the K10 montmorillonite. They are applied to Friedel-Crafts alkylations with halides, alcohols, and olefins. They are quite effective even with unactivated hydrocarbons. Isomer distribution depends little on the catalyst used. Thermodynamic equilibration does not take place, the reactions appear to be kinetically controlled. Efficiency of the catalysts bears no apparent relation to that of the corresponding Lewis acids under homogeneous conditions, and it depends on the nature of the alkylating agent. Zr(IV) and Ti(IV), in general, give the best results.