Article
Chemistry, Organic
Patrick Sand, Bernd Schmidt
Summary: The regioselectivity of two mechanistically distinct alkenylation reactions catalyzed by in situ-formed cationic transition metal complexes was studied using N-allyl-N-phenylethenesulfonamide as a model compound. Orthogonal selectivity was observed for the Ru-catalyzed C-H-activating alkenylation with acetanilides, which occurs preferentially at the electron deficient double bond, and for a Pd-catalyzed Heck-type coupling with arene diazonium salts, which occurs preferentially at the more electron rich double bond of the N-allyl substituent.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
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, Multidisciplinary
Jing Wang, Hui Wang, Zihan Wang, Linqiang Li, Cheng Qin, Xinjun Luan
Summary: This paper reports a highly chemoselective and regioselective vicinal trifunctionalization of aryl iodides using palladium/norbornene catalysis, introducing two distinct nitrogen and carbon electrophiles. The resulting products exhibit strong fluorescence emissions with full-color tunability, and product 7r can serve as a fluorescent probe specifically targeting lysosomes in living cells.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Organic
Liqin Wang, Guangjun Song, Qiufang Wu, Jiaxin Qin, Xinhong Yu, Niangen Chen, Cuiqing Li
Summary: A new palladium/norbornene-cocatalyzed Catellani-type C-H acylation and cyanation reaction has been developed without the need for directing groups, offering high yield and easy manipulation.
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Multidisciplinary
Guangrong Meng, Liang Hu, Martin Tomanik, Jin-Quan Yu
Summary: Pd-II-catalyzed beta- and gamma-C(sp(3))-H heteroarylation of free carboxylic acids using pyridine-pyridone ligands overcomes limitations in selective functionalization and compatibility with heteroatoms. A sequence of three consecutive C(sp(3))-H activation reactions of pivalic acid constructs diverse quaternary carbon centers containing heteroaryls, offering a valuable tool for breaking new ground in medicinal chemistry.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Nelson Y. S. Lam, Zhoulong Fan, Kevin Wu, Han Seul Park, Su Yong Shim, Daniel A. Strassfeld, Jin-Quan Yu
Summary: This study summarizes key factors for achieving high selectivity at defined aryl positions by analyzing 119 structurally unique remote DTs, which are experimentally corroborated through the development of new aliphatic meta and para-selective DTs for electronically unbiased arenes. These empirical rules, summarizing key distance and geometric factors, are expected to be useful tools for the future development of site-selective arene C-H activation and other reactions relying on covalent/noncovalent DT-mediated remote regioselection.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Patrick Sand, Bernd Schmidt
Summary: The palladium-catalyzed oxidative Heck reaction, also known as Fujiwara-Moritani reaction, is used for the synthesis of styrenylsulfonyl compounds, involving acetanilides and vinylsulfonyl compounds with benzoquinone as the oxidant. While potassium peroxodisulfate is a superior oxidant for coupling with acrylates, it does not provide any coupling products with olefins. The traceless removal of the catalyst directing group was demonstrated for 2-arylethene sulfones.
Review
Chemistry, Physical
Xinyue Tan, Huadong Wang
Summary: This review summarizes the recent progress in the catalytic C-H borylation of (hetero)arenes, with a focus on synthetic application and reaction mechanisms.
Article
Chemistry, Multidisciplinary
Marti Garcon, Nicolette Wee Mun, Andrew J. P. White, Mark R. Crimmin
Summary: This study demonstrates a new method of transforming C-H bonds into C-Zn bonds using a palladium catalyst and zinc hydride reagent, which has been successfully applied to various types of arenes with high selectivity. Mechanistic studies show that heterometallic complexes play a crucial role in the catalytic process.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Cheng-Hao Gu, Zhen Zhang, Shuo-Jie Shen, Hua-Jin Xu, Yi Hu
Summary: To further promote the practical application of C-H activation, researchers aim to develop green and mild reaction conditions, especially for remote C-H activation reactions. In this study, a new cheap and powerful (n-Bu)4NNO3 oxidant was reported, which enables Pd(II) catalyzed sp2 and sp3 C-H olefination at room temperature. This advancement contributes to making C-H functionalization more economical and environmentally benign.
Article
Chemistry, Organic
Ashfaq Ahmad, Himangsu Sekhar Dutta, Mohit Kumar, Raziullah, Manoj Kumar Gangwar, Dipankar Koley
Summary: A palladium catalyzed directing group assisted cross-coupling reaction has been developed for the synthesis of β-arylethylamine derivatives. The method is applicable to a wide range of substrates and can tolerate the presence of various external additives.
Article
Chemistry, Multidisciplinary
Xiaolin Shi, Zemin Wang, Yuxiu Li, Xiaowei Li, Xiangqian Li, Dayong Shi
Summary: The study reports a challenging palladium-catalyzed remote C4-H phosphonylation of indoles using a radical approach. The method not only provides a new synthetic pathway, but also unexpectedly obtained C6-phosphonylated indoles, suggesting a potential strategy for future cross-coupling reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Till Schmidt-Raentsch, Hendrik Verplancke, Jonas N. Lienert, Serhiy Demeshko, Matthias Otte, Gerard P. Van Trieste, Kaleb A. Reid, Joseph H. Reibenspies, David C. Powers, Max C. Holthausen, Sven Schneider
Summary: In this study, the synthesis of a formal terminal nitride complex of palladium was reported, and it was characterized through photocrystallography, magnetism, and computational methods. Based on this complex, a photocatalytic protocol for aldehyde C-H trimethylsilylamidation was developed, which exhibited inverted nucleophilic selectivity. This first example of catalytic C-H nitrogen atom transfer has significant implications for obtaining primary amides.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
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, Multidisciplinary
Ling Dai, Shuling Yu, Yinlin Shao, Renhao Li, Zhongyan Chen, Ningning Lv, Jiuxi Chen
Summary: In this study, an efficient protocol for the assembly of the pharmaceutically and biologically valuable oxazole skeleton from simple arenes and functionalized aliphatic nitriles was achieved for the first time. The reaction proceeds efficiently under redox-neutral conditions with high atom-economy, suggesting that C-H bond cleavage of the simple arenes might be the rate-determining step.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Ankit Kumar Mittal, Gaurav Prakash, Pramod Pathak, Debabrata Maiti
Summary: This paper presents a safer, scalable, and continuous process for synthesizing picramide. The process consists of two steps: nitration of p-nitroanisole (PNAN) to 2,4,6-trinitrianisole (TNAN) in the first step, and ammonolysis of TNAN to picramide in the second step. Flow optimization resulted in yields of 90% and 98% for step-1 and step-2 respectively, with HPLC purity greater than 99% for the obtained picramide. The flow process offers significant advantages in selectivity and yield compared to the batch process in step-1. The optimized flow process was successfully scaled up to a production rate of 25 g/hr in a laboratory flow reactor, demonstrating its suitability for commercial-scale production of picramide.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Mazen Elsaid, Robbie Ge, Chong Liu, Debabrata Maiti, Haibo Ge
Summary: This paper reports the first development of direct Pd-catalyzed C-H alkylation and acylation of carbazoles assisted by norbornene (NBE) as a transient directing mediator. The method does not require the installation of a pre-installed directing group, greatly expanding the applicability of carbazole compounds and improving reaction efficiency.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Sruti Mondal, Tanmoy Pain, Astam Mandal, Debabrata Maiti, Sanjib Kar
Summary: The reaction of antimony(III) corroles with nitrosonium tetrafluoroborate in the presence of air led to the formation of trans-difluoroantimony(V) 3,17-dinitro-corrole complexes. The formation of these complexes involves a possible intermediate trans-dinitrosylantimony(V) corrole compound. In situ FT-IR spectra confirmed the presence of these intermediate species. The trans-difluoroantimony(V) 3,17-dinitro-corrole complexes, characterized by various spectroscopic techniques, can catalyze oxygenation reactions by forming singlet oxygen under photo-redox conditions in the presence of air and light at ambient temperature.
APPLIED ORGANOMETALLIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Mohamed Mokhtar, Subir Panja, Abdulmohsen Alshehri, Wael Halawani, Debabrata Maiti
Summary: A nanocomposite catalyst based on CuO/ZnO/ZrO2 materials was developed using the coprecipitation method and subsequent calcination. The catalysts were characterized using TGA, XRD, SEM, and N-2-physisorption analysis. The nanocomposite catalyst with a Cu/Zn ratio of 1:1 exhibited the smallest particle size and largest surface area. It demonstrated excellent efficacy for the oxidation of benzylic alcohol under optimal conditions and could be used for up to three catalytic cycles with minimal loss of activity.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Review
Chemistry, Multidisciplinary
Prabhat Kumar Baroliya, Mukesh Dhaker, Subir Panja, Shaeel Ahmed Al-Thabaiti, Soha M. Albukhari, Qana A. Alsulami, Arnab Dutta, Debabrata Maiti
Summary: Electrochemically promoted transition metal-catalyzed C-H functionalization is a promising area of research, but it is still at an early stage compared to traditional chemical-based oxidizing agents. Recent reports have shown increased attention on electrochemically promoted metal-catalyzed C-H functionalization. From the perspective of sustainability and cost effectiveness, electrochemically promoted oxidation of a metal catalyst offers a mild, efficient, and atom-economical alternative to traditional chemical oxidants. This Review discusses advances in the field of transition metal-electrocatalyzed C-H functionalization and how electricity enables metal-catalyzed C-H functionalization in an economic and sustainable way.
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, Applied
Suman Maji, Sukumar Pradhan, Karishma Pidiyara, Siddhartha Maiti, Shaeel A. Al-Thabaiti, Debabrata Maiti
Summary: This work presents a palladium(II)-catalyzed regioselective C8-H olefination of 1-naphthamides. Notably, naphthamide fused lactam 2,3-dihydro-1H-benzo[de]isoquinolin-1-one derivatives were synthesized in a particular class of napthamides. The reaction showed good compatibility with a diverse range of acrylates and styrenes, providing the desired products with high yields and tolerance to various functional groups. The developed strategy was further employed for the synthesis of different drug derivatives.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Argha Saha, Chiranjit Sen, Srimanta Guin, Chandan Das, Debajit Maiti, Subhabrata Sen, Debabrata Maiti
Summary: We have developed a photoinduced protocol for the synthesis of pharmaceutically important oxazole molecules using diazo- and nitrile-containing reactants. The process involves the initial photolysis of the diazo compound to afford singlet carbenes, which are tapped by nitriles in a [3+2] cycloaddition fashion to give substituted oxazoles. The protocol is applicable for the synthesis of diverse oxazoles and can be used for drug synthesis and isotope labeling.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Ankit Kumar Mittal, Pramod Pathak, Gaurav Prakash, Debabrata Maiti
Summary: Nitrate esters are important organic compounds with wide application. We have developed a continuous flow process for their production, which is safer and more efficient.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
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)
Review
Chemistry, Physical
Tapas Kumar Achar, Shaeel Ahmed Al-Thabaiti, Mohamed Mokhtar, Debabrata Maiti
Summary: Chiral poly(hetero)cyclic compounds are commonly found in bioactive molecules, natural products, and functional materials. The synthesis of these compounds typically involves tedious classical synthetic procedures. However, recent advancements in transition-metal-catalyzed C-H bond activation and cyclization reactions have provided a more efficient approach. Despite these advancements, the synthesis of chiral annulated products remains challenging. This review highlights recent advancements in asymmetric annulation reactions catalyzed by chiral CpxM(III) complexes, focusing on the mechanistic understanding of the developed protocols.
Article
Chemistry, Multidisciplinary
Debajit Maiti, Argha Saha, Srimanta Guin, Debabrata Maiti, Subhabrata Sen
Summary: In this study, a reagent-less electro-photochemical reaction using electricity and blue LED was developed for the synthesis of diverse substituted oxazoles, diastereo-selective imide-fused pyrroles, and tetrahydroepoxy-pyridines. Mechanistic investigation confirmed the formation of carbene radical anions. The reaction has significant implications for the synthesis of important heterocycles.
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)
