Article
Chemistry, Physical
Guoshuai Li, Yifei Yan, Pengfei Zhang, Xiaohua Xu, Zhong Jin
Summary: A new palladium-catalyzed meta-selective C-H olefination of aromatic carbonyl compounds was achieved by utilizing noncovalent hydrogen-bonding interaction directed by engineered N,N'-substituted ureas, demonstrating site-selective control without the need for prior stoichiometric installation and removal of directing groups.
Article
Chemistry, Physical
Raju S. Thombal, Peter Yuosef M. Rubio, Daesung Lee, Debabrata Maiti, Yong Rok Lee
Summary: Metal catalyzed cascade C-H activation/annulation is a highly promising approach for the construction of aromatic and heteroaromatic compounds. Pd-complexes play a crucial role in this method, enabling high catalytic efficiency through the activation of molecules bearing a directing group.
Review
Chemistry, Organic
Monak Patel, Uppuluru Ajay, Kishor Padala, Togati Naveen
Summary: Olefins are low-cost starting materials that can be obtained in bulk quantities from petrochemical feedstocks and renewable resources. In recent years, synthetic chemists have shown strong interest in the transition metal-catalyzed unactivated olefin functionalization, with cobalt catalysts being particularly favored for C-H functionalization reactions.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Hui Xie, Mei Zhong, Xiao-Tong Wang, Jia-Qiang Wu, Yan-Qu Cai, Jidan Liu, Bing Shu, Tong Che, Shang-Shi Zhang
Summary: This study presents a novel method for the direct C(sp(2))-H amination of arenes using Cp*Ir(iii) and Cp*Rh(iii) catalysts with the assistance of a thioether directing group. The protocol is redox-neutral, has a broad substrate scope, high functional-group compatibility, and generates the desired products in moderate to excellent yields. This represents the first example of a thioether-directed Cp*Ir(iii) and Cp*Rh(iii)-catalyzed C(sp(2))-H amination reaction, and also demonstrates the use of azide compounds as a diversified and robust aminating reagent in thioether-directed C-H functionalization reactions.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Physical
Yasunori Minami, Hitomi Miyamoto, Yumiko Nakajima
Summary: Furfural and its derivatives were subjected to alkenylation with alkynes via alpha-C-H activation in the presence of a palladium/carboxylic acid catalyst, leading to the formation of corresponding single and double alkenylated products while maintaining the reactivity of the aldehyde group. This catalytic system enabled selective alkenylation of furan substrates with electron-withdrawing substituents.
Article
Chemistry, Applied
Francisco Villalba, Ana C. Albeniz
Summary: The pyridone fragment in the ligand plays a crucial role in the C-H activation step of the oxidative Heck reaction. The presence of bipy-6-OH is required for the alkenylation of low acidity fluoroarenes, while it is detrimental for high acidity fluoroarenes. The use of catalytic amount of sodium molybdate as a base is optimal in all these reactions.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Applied
Balazs L. Toth, Gergo Salyi, Attila Domjan, Orsolya Egyed, Attila Benyei, Zsombor Gonda, Zoltan Novak
Summary: The study reports a stereoselective procedure for direct fluorovinylation of aromatic and heteroaromatic scaffolds utilizing palladium-catalyzed ortho C-H activation reaction of aniline derivatives. The use of non-symmetrical aryl(fluoroalkenyl)-iodonium salts as fluoroalkenylating agents allows mild reaction conditions, and feasibility has been demonstrated through over 50 examples.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Review
Chemistry, Applied
Kelvin Urbina, David Tresp, Karli Sipps, Michal Szostak
Summary: Indole is an important heterocycle in organic synthesis, natural products, and drug discovery, and recent research on the selective functionalization of indole has made significant advances, driven mainly by transition metal catalysis and metal-free methods. Future trends include transition-metal-catalyzed functionalization at different positions and transition-metal-free functionalization.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Kananat Naksomboon, Enrique Gomez-Bengoa, Jaya Mehara, Jana Roithova, Edwin Otten, M. Angeles Fernandez-Ibanez
Summary: Pd-catalyzed C-H functionalization reactions of non-directed substrates have emerged as a promising alternative to the use of directing groups. A new type of S,O-ligand has been found to be highly efficient in promoting Pd-catalyzed C-H olefination reactions of non-directed arenes, although its role in the process was unclear. Through various mechanistic tools, it was discovered that C-H activation is the rate-determining step and the S,O-ligand triggers the formation of more reactive Pd cationic species, explaining the observed acceleration of the reaction. These findings provide important insights into the role of the S,O-ligand in promoting Pd-catalyzed C-H functionalization reactions.
Article
Chemistry, Organic
Verena Sukowski, Wen-Liang Jia, Rianne van Diest, Manuela van Borselen, M. Angeles Fernandez-Ibanez
Summary: The study presents the C-H olefination of substituted anisole derivatives using a Pd/S,O-ligand catalyst, allowing for a broad range of substituted aryl ethers with good yields and site selectivities. The methodology is straightforward and can be performed under aerobic conditions.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Sif T. Linde, Vasco Corti, Vibeke H. Lauridsen, Johannes N. Lamhauge, Karl Anker Jorgensen, Nomaan M. Rezayee
Summary: This article presents a method for obtaining a versatile chiral biaryl structure through C-H halogenation reactions using high-valent Pd catalysis and chiral transient directing groups. The method is scalable, moisture and air insensitive, and in some cases, requires low Pd-loadings of only 1 mol%. Chiral mono-brominated, dibrominated, and bromochloro biaryls can be prepared in high yield and excellent stereoselectivity, serving as building blocks for various reactions with orthogonal synthetic handles.
Article
Chemistry, Organic
Eisuke Sato, Ayaka Yukiue, Koichi Mitsudo, Seiji Suga
Summary: Anodic oxidation was used to achieve the aromatization of 1,2,3,4-tetrahydrocarbazoles. Nitrogen-protected tetrahydrocarbazoles were converted to carbazoles with the use of bromide as a mediator. The presence of AcOH and the inexpensive bromide source LiBr allowed for efficient transformation.
Article
Chemistry, Organic
Shuo Li, Xian Xu, Qianlin Sun, Xin Xu
Summary: This study presents a intramolecular C(sp3)-H annulation of functionalized 2,6-lutidines catalyzed by an organocalcium hydride. The reaction provides a streamlined approach for the synthesis of tetrahydro-1,5naphthyridines and hexahydropyrido[3,2-b]azocines derivatives with high efficiency and broad substrate scope. The isolation and structural characterization of a calcium alkyl complex confirms its role as the catalytic intermediate.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Tao Liu, Lingli Han, Jing Zhang, Gang Lu
Summary: Density functional theory calculations were used to investigate the competing pathways of rhodacycle intermediates in Rh(III)-catalyzed annulations of 2-alkenyl phenols and 2-alkenyl anilides with alkynes. The results reveal that the multiple pathways of eight-membered rhodacycles can be subtly tuned to give specific cyclic products. The formation of different cyclic products from 2-alkenyl phenols and 2-alkenyl anilides is governed by different pathways involving the dissociation of Rh-O bond and intramolecular olefin migratory insertion, respectively.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Rie Yoshimoto, Attila Taborosi, Qiyuan He, Yusuke Ano, Naoto Chatani, Seiji Mori
Summary: The reaction between aromatic amides and maleimides, catalyzed by palladium, leads to the formation of a product with double C-H bond activation, occurring at both the benzylic and meta positions. Computational chemistry studies reveal a stepwise mechanism involving a six-membered palladacycle, maleimide insertion, protonation of the Pd-N bond, and activation of the meta C-H bond. The site selectivity is determined by the interaction energy controlling the insertion of maleimide into the Pd-C(sp(3)) bond. The meta C-H bond activation step is identified as the rate-determining step based on the energetic span model. The 2-thiomethylphenyl group is found to function effectively as a directing group due to strong Pd-S bonding and the destabilizing effect of the deformation energy.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
