Article
Chemistry, Inorganic & Nuclear
Lingyu Kong, Yajie Chou, Muriel Albalat, Marion Jean, Nicolas Vanthuyne, Stephane Humbel, Paola Nava, Herve Clavier
Summary: The concept of atropisomeric N-heterocyclic carbene (NHC)-metal complexes with C-2-symmetry was extended to palladium-based complexes. Through a comprehensive study of NHC precursors and screening of various NHC ligands, the formation of meso complexes was successfully circumvented. Eight atropisomeric NHC-palladium complexes were prepared and obtained with high enantiopurities through efficient chiral HPLC resolution. These complexes demonstrated good activity in the intramolecular alpha-arylation of amides, leading to the isolation of cyclic products with excellent enantioselectivities (up to 98% ee).
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Niklas F. Both, Anke Spannenberg, Haijun Jiao, Kathrin Junge, Matthias Beller
Summary: The use of bis(NHC) manganese(I) complexes 3 as catalysts for the hydrogenation of esters was investigated. Various aromatic and aliphatic esters were successfully hydrogenated at mild temperatures and low catalyst loadings using complexes 3 with KHBEt3 as additive, highlighting the efficiency of the novel catalytic system. Additionally, the versatility of the developed catalytic system was demonstrated by the hydrogenation of other substrate classes like ketones, nitriles, N-heteroarenes, and alkenes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Thomas P. Nicholls, Zhongfan Jia, Justin M. Chalker
Summary: An electrochemical synthesis method has been developed for the production of gold(I)-N-heterocyclic carbene (Au-NHC) complexes. This method allows for the production of complexes without any by-products, which can be directly used as catalysts without purification.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Le Dung Pham, Red O. Smith-Sweetser, Briana Krupinsky, Carolyn E. Dewey, Jessica R. Lamb
Summary: This study demonstrates that NHC-CDI adducts can be used as masked precursors for switchable organocatalysis, and the CDI substituents can control the reaction profile without changing the NHC structure. By controlling the electronic variations and perturbations on the CDI, the catalytically active temperature and catalyst release range can be controlled.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Xiangzhang Tao, Qing Wang, Lingyu Kong, Shengyang Ni, Yi Pan, Yi Wang
Summary: A Markovnikov-selective hydroacylation of alkenes has been achieved by the synergistic merger of cobalt, photoredox, and N-heterocyclic carbene catalysis. The closely interconnected catalytic cycles enable Co(III) generation through photochemical oxidation, eliminating the need for chemical oxidants or anodizing processes. This mild and operationally simple protocol efficiently converts a wide range of commercially available alkenes and aroyl fluorides into ketones with high yield and branched selectivity.
Review
Chemistry, Multidisciplinary
Simon Stenkvist, Sara Bacaicoa, Ellymay Goossens, Henrik Sunden
Summary: The use of oxidative N-heterocyclic carbene (NHC) catalysis has gained significant interest due to the ease of transforming simple starting materials into highly functionalized products. However, the use of stoichiometric amounts of high molecular weight oxidants usually generates equivalent amounts of waste. To address this issue, the use of oxygen as the terminal oxidant in NHC catalysis has been developed. This review covers the development of aerobic oxidative carbene catalysis, including NHC-catalyzed reactions with oxygen, strategies for oxygen activation, and selectivity issues under aerobic conditions.
Article
Chemistry, Physical
Fangfang Guo, Jiean Chen, Yong Huang
Summary: Recently, chiral N-heterocyclic carbenes (NHCs) have been established as powerful catalysts for enantioselective bond-forming processes via noncovalent interactions. A bifunctional NHC with an embedded hydrogen-bonding motif has been reported in this study, showing remarkable tolerance of various Michael acceptors in an asymmetric aza-conjugate addition reaction, with catalytic efficiency far exceeding that of the benchmark tertiary amine-thiourea scaffold.
Article
Chemistry, Multidisciplinary
Tsubasa Inokuma, Ken-ichi Yamada
Summary: Our recent efforts focused on the development of N-Heterocyclic carbene (NHC)-catalyzed asymmetric reactions. We observed the significant effects of remote substitution at the carbene carbon of NHCs in acylation reactions and a significant enhancement of enantioselectivity by the addition of carboxylate anions. By applying this concept, we achieved excellent enantioselectivities in kinetic resolutions of cyclic and acyclic alcohols. The effects of remote substitution were also observed in intramolecular Stetter reaction and intermolecular benzoin reaction.
Article
Chemistry, Physical
Hao Liu, You-Feng Han, Zhong-Hua Gao, Chun-Lin Zhang, Congyang Wang, Song Ye
Summary: The cooperative N-heterocyclic carbene/nickel-catalyzed redox-neutral hydroacylation of 1,3-dienes with aldehydes in water was successfully achieved, providing synthetically useful compounds with high atom economy. This study demonstrated the compatibility of NHC catalysis with nickel catalysis and utilized water as the sole solvent, which is rarely reported in cooperative metal/organic catalytic systems.
Article
Chemistry, Multidisciplinary
Louis Monsigny, Anna Kajetanowicz, Karol Grela
Summary: This review discusses a distinct class of ruthenium olefin metathesis catalysts with unsymmetrical N-heterocyclic carbene (uNHC) ligands, highlighting their advantages such as thermodynamic stability, chemical latency, selectivity, and compatibility with green solvents in specialized metathesis transformations. Despite being niche, uNHC complexes have the potential to be implemented in various industrial processes like valorization of Fischer-Tropsch olefin fractions, ethenolysis of renewable products, and modern pharmaceutical production.
Review
Chemistry, Inorganic & Nuclear
Halliru Ibrahim, Muhammad D. Bala, Holger B. Friedrich
Summary: This review elaborates on the chronological development of imino-NHC ligands and their complexes with late first-row transition metals utilized in homogeneous catalysis. Imino-NHC ligands have gained popularity due to their general stability, better resistance to degradation, and suitable coordinative and electronic properties for various catalytic transformations.
COORDINATION CHEMISTRY REVIEWS
(2022)
Article
Chemistry, Organic
Jianming Zhang, Zheng Liang, Simiao Zhang, Lei Chen, Xiaoxue Wang, Yuchan Wang, Jie Feng, Tao Lu, Ding Du, Jian Gao
Summary: An N-heterocyclic carbene-catalyzed asymmetric [3 + 2] annulation of enals with propargylic ketimines has been developed for the facile and enantioselective construction of gamma, gamma-disubstituted pyrrolidin-2-ones. This method features mild reaction conditions, wide functional group tolerance, easy scalability, and high level of enantioselectivity, enriching the chemistry of NHC-bound homoenolates involved in the synthesis of gamma-lactams bearing gamma-quaternary stereogenic centers from acyclic ketimines.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Hui Shen, Zhen Xu, Maryam Sabooni Asre Hazer, Qingyuan Wu, Jian Peng, Ruixuan Qin, Sami Malola, Boon K. Teo, Hannu Hakkinen, Nanfeng Zheng
Summary: Deciphering the atomic arrangement of hybrid surface ligands on metal nanoparticles is a key step towards understanding their complex geometrical and electronic structures, which can have potential bio-applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Bao-Gui Cai, Qian Li, Claire Empel, Lei Li, Rene M. Koenigs, Jun Xuan
Summary: In this study, we reported the visible light and N-heterocyclic carbene (NHC) jointly promoted multicomponent carbene transfer reactions. Two kinds of important hydroxamic acid esters were obtained in good yields under optimized reaction conditions depending on the reaction media used. The utility and practicality of this method were demonstrated through mild reaction conditions, excellent functional group tolerance, useful synthetic transformations, and successful modification of natural products and drug molecules.
Article
Chemistry, Physical
Zhipeng Pei, Qinyu Qiao, Cunxi Gong, Donghui Wei, Michelle L. Coote
Summary: This study reveals the strong electrostatic effects and stabilizing dispersion interactions in the NHC center dot H+ catalyzed decarboxylation reaction. Additionally, charged functional groups are shown to enhance the electrostatic effects and catalytic effects even further.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
