Efficient and phosphine-free bidentate N-heterocyclic carbene/ruthenium catalytic systems for the dehydrogenative amidation of alcohols and amines

Xuan Jun Wu, Hua Jing Wang, Zhao Qi Yang, Xiao Sheng Tang, Ye Yuan, Wei Su, Cheng Chen, Francis Verpoort

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The direct amide synthesis from alcohols and amines applying various transition metal catalysts has been demonstrated as an attractive and promising process. Among various catalytic systems, N-heterocyclic carbene (NHC)-based ruthenium (Ru) ones have been testified to be active for this atom-economic transformation. Although a variety of imidazole-based NHC/Ru catalytic systems were reported to be active for this reaction, the benzimidazole-based analogs exhibited higher catalytic performance in most cases. However, these catalytic systems, which comprise a monodentate NHC ligand and a Cl or phosphine ligand as the key components, require relatively high catalyst loadings. In order to obtain more active and robust catalytic systems, we aim to bridge two monodentate ligands with one bidentate NHC ligand. Therefore, a number of C NHC C bidentate NHC precursors were designed and synthesized. Through screening of the NHC precursors and other reaction conditions, potent and phosphine-free bidentate NHC/Ru catalytic systems were discovered for the efficient amide synthesis. Interestingly, from the in situ generated catalytic system, two NHC/Ru intermediates were isolated and structurally confirmed by X-ray crystallography. Notably, these two complexes are active for the amide synthesis even at a low catalyst loading of 0.5 mol%, which could verify that they should be key intermediates during the catalysis. Probably, the current catalytic systems, featuring high efficiency and ready accessibility, could be valuable for more interesting applications.

Original languageEnglish
Pages (from-to)563-570
Number of pages8
JournalOrganic Chemistry Frontiers
Volume6
Issue number5
DOIs
Publication statusPublished - 7 Mar 2019

Fingerprint

phosphine
Ruthenium
Amines
Alcohols
Amides
Ligands
Catalysts
carbene
X ray crystallography

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Efficient and phosphine-free bidentate N-heterocyclic carbene/ruthenium catalytic systems for the dehydrogenative amidation of alcohols and amines. / Wu, Xuan Jun; Wang, Hua Jing; Yang, Zhao Qi; Tang, Xiao Sheng; Yuan, Ye; Su, Wei; Chen, Cheng; Verpoort, Francis.

In: Organic Chemistry Frontiers, Vol. 6, No. 5, 07.03.2019, p. 563-570.

Research output: Contribution to journalArticle

Wu, Xuan Jun ; Wang, Hua Jing ; Yang, Zhao Qi ; Tang, Xiao Sheng ; Yuan, Ye ; Su, Wei ; Chen, Cheng ; Verpoort, Francis. / Efficient and phosphine-free bidentate N-heterocyclic carbene/ruthenium catalytic systems for the dehydrogenative amidation of alcohols and amines. In: Organic Chemistry Frontiers. 2019 ; Vol. 6, No. 5. pp. 563-570.
@article{b70edc4f62df491d8c308b4083098a33,
title = "Efficient and phosphine-free bidentate N-heterocyclic carbene/ruthenium catalytic systems for the dehydrogenative amidation of alcohols and amines",
abstract = "The direct amide synthesis from alcohols and amines applying various transition metal catalysts has been demonstrated as an attractive and promising process. Among various catalytic systems, N-heterocyclic carbene (NHC)-based ruthenium (Ru) ones have been testified to be active for this atom-economic transformation. Although a variety of imidazole-based NHC/Ru catalytic systems were reported to be active for this reaction, the benzimidazole-based analogs exhibited higher catalytic performance in most cases. However, these catalytic systems, which comprise a monodentate NHC ligand and a Cl or phosphine ligand as the key components, require relatively high catalyst loadings. In order to obtain more active and robust catalytic systems, we aim to bridge two monodentate ligands with one bidentate NHC ligand. Therefore, a number of C NHC C bidentate NHC precursors were designed and synthesized. Through screening of the NHC precursors and other reaction conditions, potent and phosphine-free bidentate NHC/Ru catalytic systems were discovered for the efficient amide synthesis. Interestingly, from the in situ generated catalytic system, two NHC/Ru intermediates were isolated and structurally confirmed by X-ray crystallography. Notably, these two complexes are active for the amide synthesis even at a low catalyst loading of 0.5 mol{\%}, which could verify that they should be key intermediates during the catalysis. Probably, the current catalytic systems, featuring high efficiency and ready accessibility, could be valuable for more interesting applications.",
author = "Wu, {Xuan Jun} and Wang, {Hua Jing} and Yang, {Zhao Qi} and Tang, {Xiao Sheng} and Ye Yuan and Wei Su and Cheng Chen and Francis Verpoort",
year = "2019",
month = "3",
day = "7",
doi = "10.1039/c8qo00902c",
language = "English",
volume = "6",
pages = "563--570",
journal = "Organic Chemistry Frontiers",
issn = "2052-4110",
publisher = "Royal Society of Chemistry",
number = "5",

}

TY - JOUR

T1 - Efficient and phosphine-free bidentate N-heterocyclic carbene/ruthenium catalytic systems for the dehydrogenative amidation of alcohols and amines

AU - Wu, Xuan Jun

AU - Wang, Hua Jing

AU - Yang, Zhao Qi

AU - Tang, Xiao Sheng

AU - Yuan, Ye

AU - Su, Wei

AU - Chen, Cheng

AU - Verpoort, Francis

PY - 2019/3/7

Y1 - 2019/3/7

N2 - The direct amide synthesis from alcohols and amines applying various transition metal catalysts has been demonstrated as an attractive and promising process. Among various catalytic systems, N-heterocyclic carbene (NHC)-based ruthenium (Ru) ones have been testified to be active for this atom-economic transformation. Although a variety of imidazole-based NHC/Ru catalytic systems were reported to be active for this reaction, the benzimidazole-based analogs exhibited higher catalytic performance in most cases. However, these catalytic systems, which comprise a monodentate NHC ligand and a Cl or phosphine ligand as the key components, require relatively high catalyst loadings. In order to obtain more active and robust catalytic systems, we aim to bridge two monodentate ligands with one bidentate NHC ligand. Therefore, a number of C NHC C bidentate NHC precursors were designed and synthesized. Through screening of the NHC precursors and other reaction conditions, potent and phosphine-free bidentate NHC/Ru catalytic systems were discovered for the efficient amide synthesis. Interestingly, from the in situ generated catalytic system, two NHC/Ru intermediates were isolated and structurally confirmed by X-ray crystallography. Notably, these two complexes are active for the amide synthesis even at a low catalyst loading of 0.5 mol%, which could verify that they should be key intermediates during the catalysis. Probably, the current catalytic systems, featuring high efficiency and ready accessibility, could be valuable for more interesting applications.

AB - The direct amide synthesis from alcohols and amines applying various transition metal catalysts has been demonstrated as an attractive and promising process. Among various catalytic systems, N-heterocyclic carbene (NHC)-based ruthenium (Ru) ones have been testified to be active for this atom-economic transformation. Although a variety of imidazole-based NHC/Ru catalytic systems were reported to be active for this reaction, the benzimidazole-based analogs exhibited higher catalytic performance in most cases. However, these catalytic systems, which comprise a monodentate NHC ligand and a Cl or phosphine ligand as the key components, require relatively high catalyst loadings. In order to obtain more active and robust catalytic systems, we aim to bridge two monodentate ligands with one bidentate NHC ligand. Therefore, a number of C NHC C bidentate NHC precursors were designed and synthesized. Through screening of the NHC precursors and other reaction conditions, potent and phosphine-free bidentate NHC/Ru catalytic systems were discovered for the efficient amide synthesis. Interestingly, from the in situ generated catalytic system, two NHC/Ru intermediates were isolated and structurally confirmed by X-ray crystallography. Notably, these two complexes are active for the amide synthesis even at a low catalyst loading of 0.5 mol%, which could verify that they should be key intermediates during the catalysis. Probably, the current catalytic systems, featuring high efficiency and ready accessibility, could be valuable for more interesting applications.

UR - http://www.scopus.com/inward/record.url?scp=85062284287&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85062284287&partnerID=8YFLogxK

U2 - 10.1039/c8qo00902c

DO - 10.1039/c8qo00902c

M3 - Article

VL - 6

SP - 563

EP - 570

JO - Organic Chemistry Frontiers

JF - Organic Chemistry Frontiers

SN - 2052-4110

IS - 5

ER -