Solvent and temperature effects in the mechanism of allyl amination of the α-diimine complex [Pd(η3-C3H5)-(C5H4N-2-CHNC6H4OMe-4)]+ by piperidine and morpholine

doi:10.1016/0020-1693(95)90044-7

Inorganica Chimica Acta

Volume 235, Issues 1–2, July 1995, Pages 45-50

https://doi.org/10.1016/0020-1693(95)90044-7 Get rights and content

Abstract

A study is reported of the solvent and temperature effects on the equilibrium of α-diimine displacement from [Pd(η³-C₃H₅(NN′)]⁺ (NN′N′C₅H₄N-2-CHNC₆H₄OMe-4) by piperidine and morpholine and on the rates of allyl amination by these amines in the presence of activated olefins (ol) leading to [Pd(η²-ol)(NN′)] in either chloroform or methanol. The larger extent of α-diimine displacement in chloroform is essentially governed by entropy factors. ΔH° and ΔS° values for the equilibrium are discussed. The activation parameters for the slow amination reaction indicate that the reactivity differences observed are determined mainly by the entropic factor, as far as the solvent effect is concerned.

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Carbon–carbon(sp²–sp² and sp¹–sp²) and carbon–nitrogen (nucleophilic allylation) coupling processes are promoted by a catalytic system containing [PdCl(η³–C₃H₅)]₂ with the new ferrocenyl bis(difurylphosphine) 1,1′-bis[di(5-methyl-2-furyl)phosphino]ferrocene, Fc[P(Fu^Me)₂]₂. Starting from aryl bromides or allylic acetates this versatile catalyst system may be used at low palladium loadings (10⁻¹–10⁻⁴ mol%) in some Heck, Suzuki, Sonogashira and allylic amination reactions to give cross-coupled products in excellent yield. Remarkably high activity is obtained in allylic substitution reactions, providing a significant impetus for the development of bulky phosphines possessing weak σ-donicity for this particular reaction.
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^☆: This paper is dedicated to the memory of Professor Ugo Croatto.

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ArticleSolvent and temperature effects in the mechanism of allyl amination of the α-diimine complex [Pd(η3-C3H5)-(C5H4N-2-CHNC6H4OMe-4)]+ by piperidine and morpholine☆

Abstract

Tetrahedron: Asymmetry

Chem. Rev.

Angew. Chem., Int. Ed. Engl.

Inorg. Chim. Acta

Inorg. Chim. Acta

SIAM J. Appl. Math.

J. Organomet. Chem.

Article
Solvent and temperature effects in the mechanism of allyl amination of the α-diimine complex [Pd(η³-C₃H₅)-(C₅H₄N-2-CHNC₆H₄OMe-4)]⁺ by piperidine and morpholine☆