Article
Chemistry, Organic
Manisha, Shiv Shankar Gupta, Ankit Kumar Dhiman, Upendra Sharma
Summary: An efficient Rh-catalyzed method has been developed for selective C7 halogenation of N-pyrimidyl indolines, producing corresponding halides in good to excellent yields. The strategy demonstrates broad substrate scope, excellent regioselectivity for C7 functionalization of indolines, and feasibility at gram scale level. Various control experiments were conducted to understand the reaction pathway, and the applicability of the methodology was demonstrated by synthesis of indoles and post-transformation of the C7 halogenated indolines into different valuable molecules.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Ying-Ti Huang, Indrajeet J. Barve, Yi-Ting Huang, Sandip Dhole, Wei-Jung Chiu, Chung-Ming Sun
Summary: A Rh(III)-catalyzed cascade C-H activation and cyclization reaction was reported for the synthesis of benzimidazole-fused isoquinolines and benzimidazole-spiro isoindoles. Selective formation of these products can be achieved by using unsubstituted and substituted benzimidazoles at different positions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Fangyuan Chen, Junyuan Tang, Yinhui Wei, Jingyuan Tian, Hui Gao, Wei Yi, Zhi Zhou
Summary: This study successfully utilized alpha-allenols as innovative three-carbon annulation components in the Rh(iii)-catalyzed redox-neutral C-H coupling of N-phenoxyacetamides, leading to the assembly of 4-alkylidene chroman-2-ol frameworks through an unusual [3+3] annulation. Mechanistic studies revealed that synergistic coordination modes between the dual directing groups and the rhodium metal center are responsible for the observed exclusive selectivity in this transformation.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Min Seo Park, Kyeongwon Moon, Harin Oh, Ji Yoon Lee, Prithwish Ghosh, Ju Young Kang, Jung Su Park, Neeraj Kumar Mishra, In Su Kim
Summary: The Rh(III)-catalyzed C-H functionalization and subsequent intramolecular cyclization between azobenzenes and vinylene carbonate leads to the formation of different compounds, such as (2H)-indazoles or dihydrocinnolin-4-ones. Vinylene carbonate surprisingly acts as an acetaldehyde or acetyl surrogate, enabling [4 + 1] or [4 + 2] annulation reaction. This transformation stands out for its mild reaction conditions, simplicity, and excellent functional group compatibility.
Article
Chemistry, Multidisciplinary
Hang-Fei Tu, Alienor Jeandin, Marcos G. Suero
Summary: In this study, a catalytic one-step synthesis of cyclopropenium cations using readily available alkynes and hypervalent iodine reagents as carbyne sources is reported. A novel Rh-carbynoid catalytically generates monovalent cationic carbynes (:C+-R), which are then transferred to alkynes via an oxidative [2+1] cycloaddition, resulting in a new type of ester-substituted CPC. This method allows for regioselective attack of various carbon and heteroatomic nucleophiles, providing a new platform for the synthesis of valuable cyclopropenes that are difficult or impossible to make by current methodologies.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Yunkai Shi, Chao Chen, Yaxi Yang, Bing Zhou
Summary: The Rh(III)-catalyzed C7-selective C-H activation/annulation of indolines with 1,3-enynes provides access to various privileged 1,7-fused indolines with an all-carbon quaternary stereogenic carbon center. The resulting products can be easily transformed into 1,7-fused indoles, expanding the C-7 derivatization of indoles and demonstrating the synthetic utility of this methodology.
TETRAHEDRON LETTERS
(2021)
Article
Chemistry, Applied
Jingyu Zhang, Wei Xia, Saskia Huda, Jas S. Ward, Kari Rissanen, Markus Albrecht
Summary: A copper(II)-catalyzed dearomative cyclization amination of N-(2-aminobenzoyl) indoles is described, yielding tetracyclic indolines under mild conditions with good yields. Tetracyclic 5a,6-dihydroindolo[2,1-b]quinazolin-12(5H)-ones are obtained in good to excellent yields (up to 99% yield) by N-Ts bond cleavage using trifluoromethanesulfonic acid (TfOH) mediation. The resulting compounds can be easily functionalized through simple synthetic methods.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Yinsong Wu, Xinwei He, Mengqing Xie, Ruxue Li, Yi Ning, Jiahui Duan, Enshen Zhang, Yongjia Shang
Summary: The Rh(III)-catalyzed cascade nucleophilic addition/intramolecular annulation of 2-diazo-1,3-diketones with 1,3-dicarbonyl compounds has been successfully achieved to yield 6,7-dihydrobenzofuran-4(5H)-ones in up to 91% yields. The reaction tolerates a wide range of substrates and functional groups under optimized conditions and is scalable and adaptable to late-stage functionalization.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Daniel L. Priebbenow, Carol Hua
Summary: Studies on Cp*Rh(iii)-catalyzed hydroarylation of alkenes with aryl acyl silanes revealed a new synthetic strategy to access unique silicon-based indene frameworks and benzofurans. This represents the second example of rhodium-catalyzed C-H functionalization using acyl silanes as directing groups, with intramolecular aldol condensation being the key step in the process.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Jiangfei Chen, Yan-Ping Zhu, Jin-Heng Li, Qiu-An Wang
Summary: This new method involves a copper-catalyzed two-component amino-benzoyloxylation of unactivated alkenes using O-benzoylhydroxylamines as benzoyloxy sources. The chemoselectivity of the reaction depends on the position of the tethered olefins, providing a way for external-oxidant-free alkene difunctionalization. It directly utilizes O-benzoylhydroxylamines as benzoyloxy radical precursors and internal oxidants for synthesizing cyclic nitrones and isoxazolines.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Nan Ma, Zheyuan Liu, Jianhui Huang, Yanfeng Dang
Summary: Density functional theory calculations have revealed the mechanism and origins of the reactivity and regioselectivity of the Cp*Ir(iii)/Cp*Rh(iii)-catalyzed allylic C-H amidation. The rate-determining step is found to be the C-H activation, which differs between the Cp*Ir(iii) and Cp*Rh(iii) systems, affecting their reactivity and regioselectivity. The insights provided by this study will be valuable for the development of transition metal-catalyzed selective C-H amination reactions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Fu-Xiaomin Liu, Weijie Chen, Lei Ma, Kui Cheng, Zhi Zhou, Wei Yi
Summary: Here, an efficient and solvent-tunable Rh(iii)-catalyzed [5+2] annulation of N-benzo[d]imidazole indolines with 2,2-difluorovinyl tosylate has been achieved, showing an unusual 1,2-regioselectivity for the construction of monofluorinated and gem-difluorinated benzodiazepines, which exhibit potent anti-tumor activity against different cancer cell lines. Overall, this work provides a powerful complement to both C-H activation chemistry and anti-tumor lead discovery.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Organic
Wei Hu, Chao Pi, Di Hu, Xiliang Han, Yangjie Wu, Xiuling Cui
Summary: A rhodium-catalyzed cyclization of azobenzenes and vinylene carbonate has been developed to construct indazolo[2,3-a]quinolines. This method offers high yields and broad functional group tolerance, forming three C-C bonds and one C-N bond in one pot. Additionally, the resulting products exhibit favorable fluorescence properties.
Article
Chemistry, Multidisciplinary
Xiangtai Meng, Hehua Xu, Rui Liu, Yu Zheng, Shenlin Huang
Summary: This article reports an unprecedented electrocatalyic triamination of alkynes via N-H cleavage. Using TEMPO as the catalyst, this reaction allows controllable access to a variety of 2,3-diimino indolines and 2,3-diamino indoles. The reaction avoids the use of terminal oxidants, transition metals, and explosive reagents.
Article
Biochemistry & Molecular Biology
Alexandra S. Bubnova, Daria V. Vorobyeva, Ivan A. Godovikov, Alexander F. Smol'yakov, Sergey N. Osipov
Summary: An efficient method for accessing CF3-containing spiro-[indene-proline] derivatives has been developed through a Cp*Rh(III)-catalyzed tandem C-H activation/[3+2]-annulation reaction between 5-aryl-2-(trifluoromethyl)-3,4-dihydro-2H-pyrrole-2-carboxylates and alkynes. Remarkably, the dehydroproline moiety acts as a directing group, enabling selective activation of aromatic C-H bond.
Article
Chemistry, Multidisciplinary
Jeonguk Kweon, Sukbok Chang
Summary: This study demonstrates the use of an iron catalyst system for intramolecular C-H amidation to synthesize gamma-lactams from dioxazolone precursors. The reaction, catalyzed by (phthalocyanine)(FeCl)-Cl-III, proceeds through a stepwise radical pathway involving hydrogen atom abstraction and radical rebound, leading to extremely high turnover numbers of up to 47,000 under mild and aerobic conditions. The high turnover numbers and air-compatibility are rationalized based on experimental and computational mechanistic studies.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Yeong Bum Kim, Dongwook Kim, Shashikant U. Dighe, Sukbok Chang, Jung-Woo Park
Summary: This research describes a novel cobalt-catalyzed reaction for the synthesis of terminal branched allylsilanes under mild conditions. Mechanistic studies show the key intermediate and the order of bond migration involved in the process.
Article
Chemistry, Multidisciplinary
Wongyu Lee, Hyun Ji Jeon, Hoimin Jung, Dongwook Kim, Sangwon Seo, Sukbok Chang
Summary: A new relay process involving the slow in situ generation of a photoactive N-chloro species enables mild and selective access to N-centered radicals under visible light conditions, demonstrating high functional group tolerance and excellent applicability for late-stage functionalization.
Article
Chemistry, Physical
Seung Youn Hong, Dongwook Kim, Sukbok Chang
Summary: Carbocation intermediates are accessed catalytically via metal-nitrenoid transfer into alkenes, allowing for regiocontrolled elimination reactions. This method demonstrates high regioselectivity in the synthesis of valuable allylic lactams and offers the potential for enantioselective construction of gamma-lactams.
Article
Chemistry, Multidisciplinary
Suhyeon Kim, Dongwook Kim, Seung Youn Hong, Sukbok Chang
Summary: The article discusses the use of the Cp*Ir(kappa(2)-LX) system as a catalyst for alkene difunctionalization via a nitrenoid-mediated pathway, with a focus on tuning the orbital symmetry of key intermediates to improve catalytic activity. Through systematic engineering, a new catalyst system capable of stepwise nitrenoid transfer was developed, allowing for diastereoselective production of difunctionalized lactams with various nucleophiles. This mechanistic platform also enabled the development of asymmetric methods for introducing two-point chirality in (oxyallcyl)lactam products with excellent enantioselectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Yeong Bum Kim, Joonghee Won, Jeonghyo Lee, Junho Kim, Bingwei Zhou, Jung-Woo Park, Mu-Hyun Baik, Sukbok Chang
Summary: This study revealed a nickel-catalyzed intermolecular C(sp(3))-H amidation using organic azides as nitrene precursors. Enhanced amidation efficiency was achieved by introducing an electronically tailored directing group. Experimental and computational studies indicated that a putative nickel(III)-nitrenoid species serves as a key intermediate in the C-N bond-forming process.
Article
Chemistry, Multidisciplinary
Jinwoo Kim, Seongho Jin, Dongwook Kim, Sukbok Chang
Summary: This study describes the mechanistic details of the oxidatively induced reductive elimination of isolated methyl iridium and ruthenium metallacycle complexes. External oxidation was shown to facilitate the challenging CC bond formation under mild conditions. Computational analyses supported a high-valent pathway where the energy barrier for reductive elimination decreases significantly upon metallic oxidation to promote the desired CC bond formation.
BULLETIN OF THE KOREAN CHEMICAL SOCIETY
(2021)
Review
Chemistry, Multidisciplinary
Seung Youn Hong, Yeongyu Hwang, Minhan Lee, Sukbok Chang
Summary: Catalytic reactions constructing carbon-nitrogen bonds are important in synthetic and medicinal chemistry due to the prevalence of nitrogen-containing motifs in natural products and drugs. C-H amination offers a more efficient approach by directly converting C-H bonds into C-N bonds, bypassing the need for prefunctionalized substrates. The development of novel catalytic platforms utilizing metal-nitrenoids has expanded the scope of C-N bond-forming reactions and enabled the synthesis of diverse compounds.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Euijae Lee, Yeongyu Hwang, Yeong Bum Kim, Dongwook Kim, Sukbok Chang
Summary: This study investigates the enantioselective access to chiral spirolactam products via nitrenoid transfer to aromatic ipso-carbons catalyzed by Ir, highlighting the importance of enhancing secondary interactions between chiral catalysts and substrates through the introduction of a traceless O-silyl achiral auxiliary, effectively differentiating two prochiral faces of the substrates based on arenol-derived 1,4,2-dioxazol-5-one.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Xiang Lyu, Jianbo Zhang, Dongwook Kim, Sangwon Seo, Sukbok Chang
Summary: A NiH-catalyzed strategy for the hydroamidation of alkynes with dioxazolones has been reported in this study, providing synthetically useful secondary enamides in (E)-anti-Markovnikov or Markovnikov selectivity. The reaction is viable for various alkynes and functional groups, with H2O found to be essential for high catalyst turnovers. Inner-sphere nitrenoid transfer is proposed as a key component in outcompeting undesired processes in the Ni catalysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Seongho Jin, Jinwoo Kim, Dongwook Kim, Jung-Woo Park, Sukbok Chang
Summary: In this study, a Rh-catalyzed C-H acyloxylation under mild electrolytic conditions was developed, with anodic oxidation of a key rhodacyclic carboxylate intermediate enabling the product-releasing C-O bond-forming reductive elimination process. The accumulation of carboxylate near the electrode surface further induced the desired C-O bond formation, allowing ambient catalytic C-H oxygenation using stoichiometric amounts of readily accessible carboxylic acid coupling partners.
Article
Chemistry, Multidisciplinary
Jeonghyo Lee, Bora Kang, Dongwook Kim, Jia Lee, Sukbok Chang
Summary: In this study, a novel amidative alkyl migration reaction catalyzed by Cp*Co(III)(LX) using 2,6-disubstituted phenyl azidoformates as substrates was reported. The reaction mechanism involves an alkyl-walking process facilitated by a quinolinol ligand of the cobalt catalyst system, enabling both [1,2]- and [1,4]-alkyl rearrangements to allow structural variations of N-heterocyclic compounds.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Manoj Kumar Sahoo, Dongwook Kim, Sukbok Chang, Jung-Woo Park
Summary: This study demonstrates the regioselective migratory hydrofunctionalization of alkynes to produce alpha-vinylsilanes and alpha-vinylgermanes using a cobalt hydride based system. The mechanism of alkyne pi-bond migration by the cobalt hydride species is supported by both experimental and computational studies, which elucidates the unique alpha-vinyl selectivity.
Article
Chemistry, Multidisciplinary
Youyoung Kim, Dongwook Kim, Sukbok Chang
Summary: An iridium(III)-catalyzed electrooxidative intramolecular dehydrogenative C-H/N-H coupling of unprotected 2-alkenyl anilines is described, allowing the synthesis of various 3-substituted N-H indole scaffolds under undivided electrolytic conditions. Mechanistic studies indicate that the reaction proceeds through an electro-oxidation induced reductive elimination pathway.
CHEMICAL COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Torben Rogge, Nikolaos Kaplaneris, Naoto Chatani, Jinwoo Kim, Sukbok Chang, Benudhar Punji, Laurel L. Schafer, Djamaladdin G. Musaev, Joanna Wencel-Delord, Charis A. Roberts, Richmond Sarpong, Zoe E. Wilson, Margaret A. Brimble, Magnus J. Johansson, Lutz Ackermann
Summary: C-H activation has emerged as a powerful platform for molecular syntheses in various fields including natural product syntheses, pharmaceutical industries, and material sciences. This Primer summarizes best practices for experimental set-up, data deposition, and key developments in C-H activation, as well as discussing its applications and limitations.
NATURE REVIEWS METHODS PRIMERS
(2021)
