Article
Chemistry, Organic
Matteo Faltracco, Matteo Damian, Eelco Ruijter
Summary: In this study, a cascade reaction involving indolecarboxaldehydes and phosphonate-functionalized donor-acceptor cyclopropanes was used to synthesize functionalized dihydrocarbazoles and cyclohepta[cd]indoles in formal (3 + 3) and (4 + 3) cycloadditions. A slight modification to the reaction conditions also enabled access to fully aromatic heterocyclic scaffolds through the thermal loss of an electron-rich aryl moiety.
Article
Chemistry, Organic
Lingyun Yao, Jun Ying, Xiao-Feng Wu
Summary: A nickel-catalyzed carbonylative cyclization of 2-nitroalkynes and aryl iodides has been developed for the expedite construction of N-benzoyl indole scaffolds, with high efficiency and moderate to high yields. Control experiments were performed to better understand the reaction mechanism.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Matteo Faltracco, Said Ortega-Rosales, Elwin Janssen, Razvan C. Cioc, Christophe M. L. Vande Velde, Eelco Ruijter
Summary: The unexpected discovery in a seemingly trivial reaction led to the selective formation of a new carbazole product. This reaction, by carefully varying substituents, revealed a complex cascade mechanism with at least 10 elementary steps that could be directed towards different carbazole derivatives.
Article
Chemistry, Organic
Alagesan Balasubramani, Anilkumar Gunnam, Goverdhan Mehta
Summary: A one-pot synthesis of 2-azaflorenones was discovered, involving the Michael addition, orthogonal aldol reaction, dehydrative isomerization, and a 6-endo-dig-cyclization cascade. The synthesis was triggered by in situ generated ammonia in the presence of a Cu(I) catalyst and its generality was investigated. The resulting 2-azaflorenones showed enhanced functionality in their core structure. Overall, this method allows for the formation of five new bonds in one pot and exhibits green and sustainable features.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Yan Zhang, Yuye Chen, Manrong Song, Bin Tan, Yujia Jiang, Chongyuan Yan, Yuyang Jiang, Xinyue Hu, Chengqian Zhang, Wenqing Chen, Jing Xu
Summary: This article reports on the divergent total syntheses of three calyciphylline A-type alkaloids. The synthesis strategy involves efficient and diverse late-stage divinyl carbinol rearrangements, including an unprecedented oxidative Nazarov electrocyclization, an unusual allylic alcohol rearrangement, and a critical nitrile hydration step using a highly efficient donor-acceptor platinum catalyst. Additionally, the power of selective amide reductions is showcased through novel and classic tactics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Shuo Yang, Xiao-De An, Bin Qiu, Rui-Bin Liu, Jian Xiao
Summary: This study presents a novel method for one-step construction of a polycyclic indole-3,4-fused skeleton. By involving aldehydes and hydride transfer chemistry, the challenges of constructing medium-sized rings have been successfully addressed.
Article
Chemistry, Organic
Yumeng Lv, Yueshen Feng, Jiatong Dai, Yuying Zhang, Huaxuan Zhang, Zhigang Liu, Huaiji Zheng
Summary: A sequential process involving Boc-mediated oxidative dearomatization and inter/intramolecular Diels-Alder reaction was investigated. The [6.6.7.5] tetracyclic core of Calyciphylline N was assembled based on an intermolecular Diels-Alder reaction and subsequently a radical 7-endo-trig type cyclization.
Article
Chemistry, Multidisciplinary
Xi-Shang Sun, Xin Chang, Li-Min Shi, Zuo-Fei Wang, Liang Wei, Chun-Jiang Wang
Summary: A highly diastereoselective synthesis method for quaternary 3-amino oxindoles bearing an acetal unit was reported in this study. The method achieved good yields and exclusive diastereoselectivities for a range of 3-amino 3-allyl oxindoles with diverse functional groups. Further investigation showed that the method could be extended to cascade umpolung allenylation/acetalation.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Chunxiang Pan, Gaowei Wang, Hengyuan Zhao, Jianxiao Ni, Ruifeng Fan, Yongyun Zhou, Yuanbin Zhu, Shiyuan Wu, Baomin Fan
Summary: An efficient stereoselective cobalt-catalyzed hydrovinylative cyclization of 1,6-enynes with chalcones to obtain functionalized pyrrolidines has been developed. The products were furnished in good yields with up to 93% ee. A plausible mechanism through which the transformation was initiated by cyclization of 1,6-enynes is proposed.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Xiaohu Zhao, Yuqiao Zhou, Bao-Lin Li, Guangxi Du, Zhipeng Yu
Summary: A highly efficient and catalyst-free method has been developed for the dearomatization of 3-(2-isocyanoethyl)indoles using in situ generated nitrile imines. This method involves a nucleophilic/Friedel-Crafts/aza-Mannich type cascade and 1,3-dipolar cycloaddition reaction, and allows for the rapid assembly of a wide range of polycyclic indoline scaffolds with moderate to excellent yields and diastereoselectivities.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Carlos Lazaro-Milla, Hikaru Yanai, Pedro Almendros
Summary: A new sequential cyclization cascade method has been successfully developed in this study for the efficient preparation of functionalized tricyclic indoline cores bearing two contiguous stereocenters.
Article
Chemistry, Organic
Yi Cui, Jun Ren, Jiayuan Lv, Zhongwen Wang
Summary: An efficient synthesis of the aza-[5.7.6.5] tetracyclic core structure of calyciphylline D-type Daphniphyllum alkaloids has been achieved, featuring diastereoselective cyclopropanation and a [3 + 2] IMCC strategy, as well as gram-scale preparation in each step.
Article
Chemistry, Organic
Zhe Meng, Xiaoyu Zhang, Min Shi
Summary: A novel fluoroalkylation and cycloisomerization cascade reaction of ene-VDCP with ethyl iododifluoroacetate or perfluoroalkyl iodide under visible-light irradiation is reported in this study, providing the desired fluorinated cyclization products in moderate to good yields and showing good functional group tolerance. Mechanistic investigations suggest the presence of a radical chain process in this reaction.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Santosh J. Gharpure, Juhi Pal, Kaushik C. Pansuriya
Summary: A highly diastereoselective synthesis of isoxazolidine with three contiguous stereocenters mediated by TMSOTf is described. O-propargyl hydroxylamines are utilized as a novel building block for the rapid assembly of isoxazolidines via alkyne-oximium cyclization. The strategy can be used in the synthesis of enantiomerically enriched isoxazolidines, and reductive cleavage of the N-O bond allows precise control over all formed stereocenters.
Article
Chemistry, Organic
Xiaoqian He, Lei Zhu, Dan Heng, Fenru Liu, Shihan Liu, Kangbao Zhong, Chunhui Shan, Ruopeng Bai, Yu Lan
Summary: Density functional theory (DFT) calculations were used to elucidate the mechanistic insight of the Rh/Cu co-catalyzed multicomponent annulation reaction, including the formation of cyclopropane intermediate from indole, the dimetallic Michael-type addition reaction, and the intramolecular oxidation by copper enolate.
ORGANIC CHEMISTRY FRONTIERS
(2021)