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Journal ArticleDOI

Cesium effect: high chemoselectivity in direct N-alkylation of amines

12 Jan 2002-Journal of Organic Chemistry (American Chemical Society)-Vol. 67, Iss: 3, pp 674-683
TL;DR: The results demonstrated this methodology was highly chemoselective to favor mono-N-alkylation over dialkylation, offering wide applications in peptidomimetic syntheses.
Abstract: A novel method for the mono-N-alkylation of primary amines, diamines, and polyamines was developed using cesium bases in order to prepare secondary amines efficiently. A cesium base not only promoted alkylation of primary amines but also suppressed overalkylations of the produced secondary amines. Various amines, alkyl bromides, and alkyl sulfonates were examined, and the results demonstrated this methodology was highly chemoselective to favor mono-N-alkylation over dialkylation. In particular, use of either sterically demanding substrates or amino acid derivatives afforded the secondary amines exclusively, offering wide applications in peptidomimetic syntheses.

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Citations
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Journal ArticleDOI
TL;DR: This review aims to provide a concise overview of modern transition-metal catalyzed approaches to alkylamine synthesis and their functionalization.
Abstract: Transition-metal catalyzed reactions that are able to construct complex aliphatic amines from simple, readily available feedstocks have become a cornerstone of modern synthetic organic chemistry. I...

380 citations

Journal ArticleDOI
TL;DR: In this article, the use of environmentally benign and inexpensive eutectic solvents (DESs) as solvent and catalyst in the field of organic chemistry is discussed and compared.

295 citations

Journal ArticleDOI
TL;DR: In this paper, a catalytic system consisting of [Cp ∗ IrCl 2 ] 2 /NaHCO 3 for the N-alkylation of amines with primary and secondary alcohols as alkylating reagents has been developed.

274 citations

Journal ArticleDOI
TL;DR: The compound [IrCl(2)Cp*(I(nBu))] showed to be highly effective in the cross-coupling reactions of amines and alcohols, providing high yields in the production of unsymmetrical ethers and N-alkylated amines.
Abstract: A comparative study on the catalytic activity of a series of [IrCl 2 Cp*(NHC)] complexes in several C-O and C-N coupling processes implying hydrogen-borrowing mechanisms has been performed. The compound [IrCl 2 Cp*(I nBu )] (Cp* = pentamethyl cyclopentadiene; I nBU =1,3-di-n-butylimidazolylidene) showed to be highly effective in the cross-coupling reactions of amines and alcohols, providing high yields in the production of unsymmetrical ethers and N-alkylated amines. A remarkable feature is that the processes were carried out in the absence of base, phosphine, or any other external additive. A comparative study with other known catalysts, such as Shvo's catalyst, is also reported.

222 citations

Journal ArticleDOI
TL;DR: The conversion of primary amines into secondary amines has been achieved using alcohols as the alkylating agent, catalysed by [Ru(p-cymene)Cl2]2 and a bidentate phosphine ligand.

205 citations

References
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Book
01 Jan 1967
TL;DR: In this paper, the authors propose a method for using Reference Abbreviations (RABs) as a reference abbreviation for reference abbreviations in the context of bioinformatics.
Abstract: Preface vii Foreword ix General Abbreviations xi Reference Abbreviations xv Reagents 1 Author Index 527 Subject Index 618

3,626 citations

Book
01 Jan 1966

268 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of this effect on macrocyclization by means of nucleophilic substitution is discussed. But it is concluded that the cesium ion is virtually completely solvated and that carboxylates are essentially free and highly reactive.
Abstract: Cesium alkanoates (chiefly the propionate) have been investigated for their solubility, nucleophilic reactivity, and degree of ion pairing in dimethylformamide (DMF) and, in some cases, dimethyl sulfoxide (DMSO) solutions. 133Cs NMR has been used to establish the degree of ion pairing. From the data obtained it is concluded that the cesium ion is virtually completely solvated and that the carboxylates are essentially free and highly reactive. The consequences of this effect on macrocyclization by means of nucleophilic substitution are discussed.

187 citations