Article
Chemistry, Multidisciplinary
Zhi-Chao Qi, Qin-Xin Lou, Yuan Niu, Shang-Dong Yang
Summary: A palladium-catalyzed, temporary P(O) directing group assisted C-H bond arylation of carbazoles was achieved. The release of the directing group occurs spontaneously in the reaction and mechanistic studies indicate that acid is essential for N-P bond cleavage.
CHEMICAL COMMUNICATIONS
(2021)
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)
Review
Chemistry, Multidisciplinary
Uttam Dutta, Debabrata Maiti
Summary: C-H activation is a powerful synthetic tool to construct complex molecular frameworks. The use of directing groups (DGs) has resolved selectivity issues and offered a unique solution for the synthesis of complex molecules. By using different types of DGs, we achieved distal meta-C-H functionalization and gained a deeper understanding of the mechanism.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Multidisciplinary Sciences
Zhipeng Lin, Uttam Dhawa, Xiaoyan Hou, Max Surke, Binbin Yuan, Shu-Wen Li, Yan-Cheng Liou, Magnus J. Johansson, Li-Cheng Xu, Chen-Hang Chao, Xin Hong, Lutz Ackermann
Summary: Electrochemistry, with the aid of data science and artificial intelligence, is increasingly being used for molecular synthesis. The authors have successfully utilized electrocatalyzed C-H activations for selective alkenylation in late-stage drug diversification. This approach eliminates the need for directing groups, which simplifies the synthesis process and reduces waste.
NATURE COMMUNICATIONS
(2023)
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, Multidisciplinary
Jinwon Jeon, Changseok Lee, Inyoung Park, Sungwoo Hong
Summary: This article highlights the elegant and versatile approach of chelation-assisted C-H bond and alkene functionalization using bidentate directing groups, which overcomes regiocontrol issues. The focus is on two categories of results: regioselective alkene functionalization and asymmetric C-H functionalization using chiral bidentate directing groups. Additionally, density functional theory studies are discussed to elucidate the origin of regio- and stereoselectivity induced by bidentate directing groups.
Article
Chemistry, Multidisciplinary
Jyoti Dhankhar, Micha D. Hofer, Anthony Linden, Ilija Coric
Summary: This article presents a new selectivity mode for C-H arylation reactions, which is the preference for C(sp(2))-H activation next to alkyl groups. The study results indicate that this preference is related to the non-covalent interactions between the catalyst and the substrate.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Jiechun Liu, Xiaoyan Jia, Liangbin Huang
Summary: This study demonstrates for the first time the utilization of sulfilimine as a directing group for Rh(III)-catalyzed C-H activation/annulation with intermolecular and intramolecular alkyne compounds. Sulfilimine functions as a transformable directing group and an internal oxidant in the annulation with an alkyne moiety via N-S bond cleavage. Importantly, the retention of sulfilimine as a directing group is also achieved in the Rh(III)-catalyzed ortho-alkynylation with alkyne bromides.
Article
Chemistry, Organic
Saqib A. Iqbal, Clement R. P. Millet, Juergen Pahl, Kang Yuan, Michael J. Ingleson
Summary: Two templates used in meta-directed C-H functionalization under metal catalysis cannot direct meta-C-H borylation under electrophilic borylation conditions. One template forms Lewis adducts with Lewis basic sites in the presence of BCl3, while the other template, containing an amide linker, only leads to amide directed ortho C-H borylation with no pyridyl directed meta borylation. The selective ortho borylation of the aniline derived unit in the template suggests a higher barrier to pyridyl directed meta borylation and the need for customized templates for enabling meta-directed electrophilic borylation.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Dasari Srinivas, Kurella Mounika, Gedu Satyanarayana
Summary: In this study, the first microwave-assisted remote-C-H functionalization was achieved with the help of a simple nitrile directing template. This method exhibited a wide range of substrate scope by enabling meta-C-H arylation, acetoxylation, and cyanation. Moreover, the microwave-accelerated meta-C-H functionalization was highly efficient with short reaction times and preserved the yield and site selectivity. Additionally, the diversification of the ibuprofen drug was successfully achieved through arylation, acetoxylation, and cyanation. Importantly, the study presented a new method for meta-dual-hetero functionalization.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Perla Ramesh, Chinnabattigalla Sreenivasulu, Koteswara Rao Gorantla, Bhabani S. Mallik, Gedu Satyanarayana
Summary: Remote meta-selective C-H bond functionalization of aromatic compounds is a challenging yet valuable goal in organic chemistry. Researchers have developed a simple and inexpensive removable aliphatic template as a directing group template to promote meta-C-H olefination of arenes. This methodology is efficient, economical, and tolerant of a wide range of substituted arenes and olefin coupling partners.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Jing Jiang, Dandan Yuan, Congzhe Ma, Wanbin Song, Yaoyu Lin, Lihong Hu, Yinan Zhang
Summary: An efficient divergent approach of Pd-catalyzed C-H oxygenation of polyaromatic rings is described, utilizing reversible directing groups to achieve regiospecific oxygenation. Mechanistic investigation, including deuterium-labeling experiments and DFT calculations, reveals the crucial role of tunable ligand-assisted C-H bond cleavage during the reaction process.
Article
Chemistry, Multidisciplinary
Chaolumen Bai, Bao Chao, Tegshi Muschin, Agula Bao, Menghe Baiyin, Dan Liu, Yong-Sheng Bao
Summary: This study reports the regioselective cross-coupling reactions in the o-methyl benzaldehyde frameworks using palladium catalysis, K2S2O8 or [F+] reagents as oxidants, and unactivated arenes as substrates/solvents. The regiospecificity is controlled by [5,6]-fused or [6,5]-fused palladacycle intermediates formed from Pd-chelation with specific transient directing groups and C-H activations.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Zhiyong Hu, Florian Belitz, Guodong Zhang, Florian Papp, Lukas J. Goossen
Summary: In the presence of [p-cymene)RuCl2](2), (E)-configured alkenyl bromides coupled with aromatic carboxylates to form orthovinylbenzoic acids in high yields, showing excellent functional group tolerance. Mechanistic studies revealed that the selectivity of this reaction is due to (E)-configured alkenyl bromides undergoing smooth coupling while the (Z)-isomers are rapidly eliminated to form alkynes.
Article
Chemistry, Multidisciplinary
Mixiang Tian, Lidong Shao, Xiaosan Su, Xuhong Zhou, Honglei Zhang, Kun Wei, Ruifen Sun, Junliang Wang
Summary: A new method has been developed for selective oxygenation of benzaldehydes and benzylic amines at the ortho positions to prepare fluoroalkyl aryl ethers.
Article
Chemistry, Physical
Saghnik Saha, Jayabrata Das, Shaeel Ahmed Al-Thabaiti, Soha M. Albukhari, Qana A. Alsulami, Debabrata Maiti
Summary: Selective remote C-H functionalization of aliphatic chains is of great significance and remains a challenging task. The native functional group assisted C(sp(3))-H activation has emerged as a practical and efficient method for transforming aliphatic compounds. Aliphatic acids and amines have gained attention due to their unique coordination abilities with transition metals. This review summarizes the concepts and applications of remote C(sp(3))-H functionalization in aliphatic systems, providing a comprehensive understanding for beginners and experts.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Nupur Goswami, Soumya Kumar Sinha, Partha Mondal, S. Adhya, Ayan Datta, Debabrata Maiti
Summary: Regioselective and site-selective functionalization of distal C-H bonds has been a challenge due to the impact of covalently attached directing groups. Weak non-covalent interactions have been explored with Ir catalysis, but here we demonstrate a Pd-catalyzed meta-selective C-H functionalization of simple amines using anionic ligand and neutral substrate interactions. The site selectivity is governed by the H-bonding interaction between the anionic donating ligand and neutral motifs.
Review
Chemistry, Physical
Rahul Keshri, Debanjan Rana, Argha Saha, Shaeel Ahmed Al-Thabaiti, Abdulmohsen Ali Alshehri, Salem M. Bawaked, Debabrata Maiti
Summary: Transition-metal-catalyzed C(sp2)-H bond functionalization is a revolutionary strategy for efficient synthesis of complex heterocyclic frameworks. The use of free amine and alcohol as directing groups has shown significant advantages, allowing for the formation of C-C and C-heteroatom bonds and annulation cascades reactions. This review focuses on the utility of aromatic sp2-C-H functionalization directed by free amine and hydroxyl for constructing three to seven-membered N- and O-heterocycles.
Article
Chemistry, Multidisciplinary
Wajid Ali, Argha Saha, Haibo Ge, Debabrata Maiti
Summary: The merger of photocatalysis and transition-metal catalysis has led to the development of a versatile platform for environmentally friendly synthetic methods. By combining photoredox and Pd catalysis, a highly efficient, regioselective, and general meta-oxygenation protocol for various arenes has been developed. This protocol operates through a radical pathway and has been demonstrated to work for different substituted arenes using different substituents.
Article
Chemistry, Applied
Ankit Kumar Mittal, Gaurav Prakash, Pramod Pathak, Bishal Dutta, Nandita Ahalyan, Siddhartha Maiti, Debabrata Maiti
Summary: Here, we present a flow chemistry method for synthesizing tert-butyl nitrite with a high yield of 95% and a short residence time of 1min, corresponding to a space time yield of 13 g/h/mL. In addition, we demonstrate the application of tert-butyl nitrite in metal-free stereoselective nitration of alkenes. The traditional batch process, with a cycle time of 12 to 24 h, is limited for commercial production. Therefore, we developed a continuous-flow nitration process using a fixed bed column reactor, reducing the reaction time from 12 h to 3 min and achieving a faster and more efficient synthesis.
ORGANIC PROCESS RESEARCH & DEVELOPMENT
(2023)
Article
Chemistry, Physical
Nupur Goswami, Nikunj Kumar, Sukdev Bag, Puneet Gupta, Debabrata Maiti
Summary: This study investigates the palladium-catalyzed C(sp(2))-Holefination reaction of 2-arylbenzaldehyde with the aid of a temporary directing group. Computational and experimental methods are used to understand the reaction mechanism and selectivity. The results show that the reaction proceeds in three major steps and the selectivity is determined by the C-H activation step.
Article
Chemistry, Multidisciplinary
Jagrit Grover, Suman Maji, Chitrala Teja, Shaeel A. Al Thabaiti, Mohamed Mokhtar M. Mostafa, Goutam K. Lahiri, Debabrata Maiti
Summary: We have developed a novel Mn-SNS-based catalyst for the indirect hydrogenation of CO2 to methanol via formylation. Our catalyst, based on the stable and inexpensive SNS-type tridentate ligand, showed excellent recyclability and effectiveness in the formylation reaction. Various amines, including primary and secondary amines, worked well under the protocol to provide the desired formylated product in good yields. The formed formylated amines can also be further reduced at higher pressures of hydrogen.
ACS ORGANIC & INORGANIC AU
(2023)
Article
Chemistry, Multidisciplinary
Angus Olding, Curtis C. Ho, Debabrata Maiti, Alex C. Bissember
Summary: This article explores a series of case studies that examine key strategies enabling the structural authentication of important species in palladium- and nickel-catalysed C-C, C-N, and C-O cross-coupling reactions. It focuses on studies confirming the structures of challenging intermediates using X-ray crystallography, while providing mechanistic insights from these reports.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Jagrit Grover, Gaurav Prakash, Chitrala Teja, Goutam Kumar Lahiri, Debabrata Maiti
Summary: C-H thioarylation of hydrocarbon building blocks is a highly desirable synthetic transformation due to its prevalence in pharmaceuticals and organic functional materials. However, current developments rely on peroxide mediated transformations which have drawbacks of harsh reaction conditions and functional group intolerance. This study demonstrates a mild metal-free approach for C(sp(3))-H thioarylation using thioxanthone as a photo-catalyst, showing compatibility with various arenes, unactivated alkanes, and cycloalkanes. Post-synthetic modifications are also demonstrated through cross-coupling reactions and functional group interconversions.
Review
Chemistry, Multidisciplinary
Sayan Roy, Subir Panja, Sumeet Ranjan Sahoo, Sagnik Chatterjee, Debabrata Maiti
Summary: C-H functionalisation involves C-H activation and subsequent transformation, converting carbon-hydrogen bonds into carbon-carbon or carbon-heteroatom bonds. Metal-free approaches have gained attention as an alternative to transition metal-catalysed methods, providing a cost-effective and environmentally friendly way to functionalise C-H bonds.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Trisha Bhattacharya, Supratim Ghosh, Subhabrata Dutta, Srimanta Guin, Animesh Ghosh, Haibo Ge, Raghavan B. Sunoj, Debabrata Maiti
Summary: The significance of stereoselective C-H bond functionalization lies in its direct application potential to pharmaceuticals or complex chiral molecule synthesis. In this work, we harnessed the cooperative ligand approach to control two different stereogenic elements in the same molecule, resulting in the synthesis of axially chiral biaryls.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Uttam Dutta, Gaurav Prakash, Kirti Devi, Kongkona Borah, Xinglong Zhang, Debabrata Maiti
Summary: A method for directing group-assisted para-selective C-H alkynylation using Rh catalyst has been reported. The para-selectivity was achieved with the assistance of a cyano-based directing template, and remained unaltered regardless of the steric and electronic influence of the substituents. The study provides insights into the mechanistic intricacies and shows potential applications for post-synthetic modification.
Review
Chemistry, Multidisciplinary
Soumya Kumar Sinha, Pintu Ghosh, Shubhanshu Jain, Siddhartha Maiti, Shaeel A. Al-Thabati, Abdulmohsen Ali Alshehri, Mohamed Mokhtar, Debabrata Maiti
Summary: C-H activation plays a crucial role in the synthetic strategies for multi-step transformations, but its importance lies in its application in large-scale industrial processes and the synthesis of complex natural products. Recent advancements in C-H activation methodologies have led to the discovery of more efficient synthesis methods and accelerated the synthesis of complex organic compounds.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Uttam Dutta, Gaurav Prakash, Kirti Devi, Kongkona Borah, Xinglong Zhang, Debabrata Maiti
Summary: In this study, the first report on the rhodium-catalyzed para-selective C-H alkynylation is presented, and its mechanistic insights are obtained from experimental and computational studies. The para-selectivity is achieved with the assistance of a cyano-based directing template, which remains unchanged regardless of the steric and electronic influence of the substituents.