Volume 2020, Issue 11-12 p. 1123-1134
Full Paper

Phenoxylation of Alkynes through Mono- and Dual Activation Using Group 11 (Cu, Ag, Au) Catalysts

Miguel Ramos

Miguel Ramos

Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona, c/ Maria Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain

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Jordi Poater

Corresponding Author

Jordi Poater

Departament de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1–11, 08028 Barcelona, Spain

ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain

Departament de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1–11, 08028 Barcelona, Spain

E-mail: [email protected]

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Nery Villegas-Escobar

Nery Villegas-Escobar

Laboratorio de Química Teórica Computacional (QTC), Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, 7820436 Santiago, Chile

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Martí Gimferrer

Martí Gimferrer

Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona, c/ Maria Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain

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Alejandro Toro-Labbé

Alejandro Toro-Labbé

Laboratorio de Química Teórica Computacional (QTC), Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, 7820436 Santiago, Chile

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Luigi Cavallo

Corresponding Author

Luigi Cavallo

King Abdullah University of Science & Technology, KAUST Catalysis Center (KCC), 23955–6900 Thuwal, Saudi Arabia

Departament de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1–11, 08028 Barcelona, Spain

E-mail: [email protected]

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Albert Poater

Corresponding Author

Albert Poater

Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona, c/ Maria Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain

Departament de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1–11, 08028 Barcelona, Spain

E-mail: [email protected]

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Dedicated to the memory of Prof. Dr. Walter Thiel
First published: 06 January 2020
Citations: 7

Graphical Abstract

The complexity of the C–O bond formation when alkynes are mixed with alcohols in a system catalysed by one or two metal moieties is unveiled by energy decomposition analyses.

Abstract

NHC-gold(I) based catalysts have displayed outstanding results toward hydroalkoxylation of terminal and internal alkynes in solvent-free conditions and using low catalyst loadings. It has been demonstrated that, in the hydrophenoxylation reaction the gold complex is composed by two moieties that determine the rate of the reaction by activating both substrates synergistically, i.e. [Au(OR)(NHC)] and [Au(η2-alkyne)(NHC)]+. Then, these bimetallic systems act cooperatively toward the hydroalkoxylation reaction. Herein, density functional theory studies were carried out to get insights on the mechanism of hydrophenoxylation. The rate-determining step, which corresponds to the formation of the C(alkyne)–O(alcohol) bond between [Au(OR)(NHC)] and [Au(η2-alkyne)(NHC)]+, was studied using energy decomposition analyses (EDA). It was found that the C–O bond shows strong electrostatic and orbital interactions between both fragments in the homobimetallic, heterobimetallic and monogold mechanisms. Moreover, the analyses were expanded to copper and argentum, and the steric sensibility was also studied through the use of different NHC ligands, including IMes, IMe, SIMes, IPr, and IPr*, that differ on their steric demand.