Article
Chemistry, Multidisciplinary
Xin-Peng Mu, Yuan-He Li, Nan Zheng, Jian-Yu Long, Si-Jia Chen, Bing-Yan Liu, Chun-Bo Zhao, Zhen Yang
Summary: A novel method for the synthesis of cyclohepta[b]indoles in high yields was developed through a visible-light-induced, photocatalyzed [2+2]-cycloaddition/ retro-Mannich-type reaction of enaminones. Experimental and computational studies indicated that the reaction is initiated by single-electron oxidation of an enaminone moiety, leading to cyclobutane formation and rapid fragmentation in a radical-cation state to produce cyclohepta[b]indoles.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Shao-Cong Zhan, Jing Sun, Qiu Sun, Ying Han, Chao-Guo Yan
Summary: The p-TsOH catalyzed cycloaddition of various 3-vinylindoles and (indol-2-yl)diphenylmethanols in acetonitrile resulted in the formation of functionalized cyclopenta[b]indoles through a [3 + 2] cycloaddition reaction with good yields and high diastereoselectivity. Moreover, the FeCl3-catalyzed annulation reaction unexpectedly provided functionalized cyclohepta[1,2-b:4,5-b']diindoles in satisfactory yields, where a formal [4+3] cycloaddition and an unprecedented C3/C2 carbocation rearrangement were revealed by single-crystal structure determination.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Durga Prasad Hari, Guillaume Pisella, Matthew D. Wodrich, Artem Tsymbal, Farzaneh Fadaei Tirani, Rosario Scopelliti, Jerome Waser
Summary: A new oxyalkynylation/cycloaddition reaction has been reported to synthesize complex polycyclic structures under mild conditions, with high efficiency and atom economy. The obtained products can be applied as chiral ligands for metal catalysis, providing a new method for organic synthesis. Computational studies provided a first rationalization of the low activation energy for the cycloaddition reaction based on counter-intuitive favorable dispersive interactions in the transition state.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Bin Li, Jiang-Ling Shi, Ying Xia
Summary: The construction of all-carbon quaternary centers in small-ring systems is an important yet challenging task in organic synthesis. In this study, we developed a practical method for building all-carbon quaternary centers in gem-difluorinated cyclopropanes (DFCs) by utilizing gem-difluorocyclopropyl bromides (DFCBs) as general and versatile building blocks. The reaction involves the participation of a gem-difluorocyclopropyl radical intermediate, which undergoes coupling with a wide range of nucleophiles under copper catalysis.
Article
Chemistry, Organic
Bin Li, Jiang-Ling Shi, Ying Xia
Summary: In this study, a practical method for building all-carbon quaternary centers in gem-difluorinated cyclopropanes was developed using gem-difluorocyclopropyl bromides as a general building block. The reaction involves the participation of a gem-difluorocyclopropyl radical intermediate, which can undergo coupling with a wide range of nucleophiles under copper catalysis.
Article
Chemistry, Multidisciplinary
Shaomin Chen, Zhiyan Chen, Tianjian Zhang, Bo Zhao, Bo You, Minghao Li, Yanlong Gu
Summary: An efficient acid-catalyzed three-component cascade strategy was established to synthesize phenyl-substituted dihydrocyclohepta[b]indole carboxylate, which is a privileged scaffold. Another route to access tetrahydrocyclohepta[b]indoles was also discovered. These methods are practically attractive due to readily available materials, inexpensive metal-free catalysts, eco-friendly solvents, and divergent synthesis.
Review
Chemistry, Organic
Jan Gierok, Lars Benedix, Martin Hiersemann
Summary: The cyclohepta[b]indole scaffold is a significant structural motif found in natural products and pharmaceutical ingredients, with potential for research in the field of organic functional materials. Stempel and Gaich's review in 2016 comprehensively summarized the state of the art in cyclohepta[b]indoloid chemistry, leading to further exploration in literature from 2016 to 2021.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Review
Biochemistry & Molecular Biology
Taku Shoji, Shunji Ito, Masafumi Yasunami
Summary: Various synthetic methods have been developed for azulene derivatives, with 2H-cyclohepta[b]furan-2-one and its derivatives being commonly used as precursors. The synthesis of azulenes involves reactions with olefins, active methylenes, enamines, and silyl enol ethers, with resulting compounds showing promising applications.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Chemistry, Multidisciplinary
Kai Sun, Yan Zhang, Miao Tian, Zhichuan Wang, Dongyang Zhao, Shilong Wang, Shi Tang, Zhen Zhang
Summary: In this study, a novel O2N-triggered ordered addition 7-endo cyclization reaction is described, showing excellent chemo- and regioselectivity. With this strategy, structurally diverse nitro-benzo[b]azepines were successfully prepared, with a total of 28 examples. The large-scale operation and convenient N-Ts and N-Cbz deprotection demonstrate the promising utility of this methodology. Mechanistic studies suggest that the reaction proceeds through a radical pathway.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Xue Li, Haohua Chen, Qingqing Xuan, Shaoyu Mai, Yu Lan, Qiuling Song
Summary: Inspired by the body circulation of Omeprazole, a novel carbenetriggered cascades for synthesizing 2-aminobenzofuran derivatives from N-sulfonyl-1,2,3-triazoles or benzothioazole-bearing thiocarbamates was disclosed, representing an unprecedented imine derivative migration process. Additionally, desulfurizing reagent-free Barton-Kellogg-type reactions starting from N-sulfonyl-1,2,3-triazoles were achieved for the first time, with elemental sulfur confirmed as a byproduct. Experimental data and DFT calculations further explained the unique reactivity observed in these reactions.
Article
Chemistry, Multidisciplinary
Min Zhu, Hao Xu, Xiao Zhang, Chao Zheng, Shu-Li You
Summary: Herein, we report visible-light-induced intramolecular double dearomative cycloaddition of arenes, which provides a wide substrate scope for the synthesis of structurally diverse polycyclic indoline derivatives in high yields and with exclusive diastereoselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Fei-Hu Cui, Qian Li, Le-Han Gao, Kaidong Ruan, Kexin Ma, Siyuan Chen, Zhengyu Lu, Jiawei Fei, Yu-Mei Lin, Haiping Xia
Summary: The rapid synthesis of tetracyclic metallaaromatics with broad absorption is described in this study. The formation of these unique compounds involves unconventional reactions to broaden the absorption window. These condensed metallaquinolines show high photothermal conversion efficiency, stability, and have numerous potential applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Cong Guan, Jiabin Yin, Jian Ji, Jinhua Liu, Xiang Wu, Tong Zhu, Shunying Liu
Summary: A regioselective electrochemical C-H amination method using easily accessible ethers has been developed to synthesize N (2)-substituted 1,2,3-triazole. Multiple substituents, including heterocycles, were well-tolerated, and 24 examples were obtained in moderate to good yields. Control experiments and DFT calculations revealed that the electrochemical synthesis occurs through a N-tosyl 1,2,3-triazole radical cation process, promoted by single-electron transfer from the lone pair electrons of the aromatic N-heterocycle, and the desulfonation is responsible for the high N (2)-regioselectivity.
Article
Chemistry, Organic
Yujia Gao, Juan Zhang, Wenyu Shan, Weihong Fei, Jinzhong Yao, Weijun Yao
Summary: In this study, a trimerization reaction of gamma-aryl-3-butynoates was achieved through catalysis, leading to the formation of exocyclopentene derivatives with an allcarbon quaternary stereocenter. The reaction exhibited high stereoselectivity and enantioselectivity, delivering optically pure products with high enantiomeric excess values.
Article
Chemistry, Multidisciplinary
Santosh J. Gharpure, Sanyog Kumari
Summary: A protecting group-dependent diastereoselective synthesis of cyclohepta[b]indole over carbazole derivatives has been developed. The study shows that a series of organic compounds undergo specific reaction conditions to ultimately generate cyclohepta[b]indole.
CHEMICAL COMMUNICATIONS
(2023)
