Article
Chemistry, Organic
Suman Sar, Prasanta Ghorai
Summary: In this study, a highly stereo-selective P(NMe2)3 mediated intramolecular deoxygenative umpolung cascade Michael addition-initiated cyclopropanation with a diverse substrate adaptability is disclosed. This methodology allows for the expedient access to valuable 6,5,3-fused scaffolds having an all-carbon quaternary stereocenter via Kukhtin-Ramirez (K-R) adduct formation, with excellent diastereoselectivity and yields under metal-free ambient conditions. Few functional group transformations have also been successfully performed, and an asymmetric catalytic attempt using (R)-(+)-H8-BINOL has delivered good enantioselectivity.
Article
Chemistry, Organic
Suman Sar, Prasanta Ghorai
Summary: In this study, we report a highly selective P(NMe2)3 mediated intramolecular deoxygenation reaction which exhibits excellent substrate adaptability. This methodology provides a convenient access to valuable 6,5,3-fused scaffolds with an all-carbon quaternary stereocenter via Kukhtin-Ramirez (K-R) adduct formation, achieving high diastereoselectivity and yields under metal-free ambient conditions. Furthermore, successful functional group transformations and enantioselective catalytic attempts have been achieved using (R)-(+)-H8-BINOL.
Article
Chemistry, Multidisciplinary
Kaixiang Xu, Shan Mu, Huijuanzi Rao, Jialei Hu, Hanfeng Ding
Summary: The asymmetric total syntheses of (+)-vulgarisins A-E, which share a rare and highly oxygenated [5-6-4-5] tetracyclic core structure that were isolated from P. vulgaris Linn., have been described for the first time in a divergent manner. Key transformations include: 1) a catalytic asymmetric intramolecular cyclopropanation to forge the A ring bearing desired stereochemistry at C14; 2) a one-pot borylation/conjugate addition process for creation of the C1-C11 bond; 3) a Wolff ring contraction to assemble the bicyclo[3.2.0]heptane subunit (CD rings); and 4) a stereocontrolled pinacol cyclization for construction of the central B ring of the natural products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Limin Wang, Longhui Duan, Biqiong Hong, Zhenhua Gu
Summary: An acid-mediated electrophilic cyclization of 2-alkynyl-1,1'-biphenyls was used to synthesize angular, bent, and zigzag fused nonplanar conjugated organic molecules. The reaction involved a Wagner-Meerwein-type rearrangement via a spiro carbocation intermediate formed by electrophilic cyclization of a 9H-fluoren-9-one derivative. The resulting products could be further transformed into helical fluorenes with high fluorescence quantum yields.
Article
Chemistry, Organic
Young Eum Hyun, Hong-Rae Kim, Lak Shin Jeong
Summary: Asymmetric synthesis was used to synthesize conformationally locked south (S) and north (N) analogues of sugars, with different synthetic strategies employed to obtain the two conformations.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Zhanghong Guo, Xiaowei Chen, Hao Fang, Xiaowei Zhao, Zhiyong Jiang
Summary: The first enantioselective Beckwith-Enholm cyclization reaction was reported, providing a general and divergent synthetic pathway to synthesize highly valuable enantioenriched azaarene-functionalized carbocyclic and heterocyclic alcohols with high yields and selectivities. The method also offers the potential to introduce deuterium in an enantioselective manner and shows excellent antioxidant stress potential, with molecule 29 identified as a promising lead compound for antioxidant stress drug design.
SCIENCE CHINA-CHEMISTRY
(2021)
Article
Chemistry, Organic
Rong Zeng, Zheng Wang, Ruikun Peng, Peng Yan, Jie Yang, Qian Zhou, Jing Gu, Peng-Fei Zheng, Ying-Chun Chen, Qin Ouyang
Summary: Through density functional theory (DFT) calculations, the mechanism of the (4 + 1 + 1) annulations between alpha-bromo carbonyls and 1-azadienes was investigated, and the formation of a carbon anion intermediate and its attack on another alpha-bromo carbonyl substrate in a (4 + 1 + 1) manner were proposed as more reasonable processes. Based on this, a new controllable divergent (4 + 1 + 1 ') reaction was achieved by changing the feeding sequence of two different alpha-bromo substrates in the presence of tertiary amines and bases, resulting in the efficient construction of a series of fused benzofuro[3,2-b]pyridines or benzo[4,5]thieno[3,2-b]pyridines with more functional diversity.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Si-Si Luo, Hua Shen, Shi-Jia Li, Tian Cao, Yi-Peng Luo, Shu Zhang, Taigang Zhou, Xiang-Wei Liu
Summary: A convenient method for the synthesis of cyclopropyl boronates via visible-light photoredox-catalyzed borocyclopropanation of alkenes is reported. The protocol shows wide substrate scope with regard to various substituted alkenes, good functional group tolerance, and mild reaction conditions, making it a striking approach.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Dong Gao, Lei Jiao
Summary: This study presents an efficient method for constructing indoline structures with a C2-quaternary stereocenter and controlling the migrating group through aza-semipinacol rearrangement. It enables the divergent access to dearomatized indole derivatives with either a C3- or a C2-quaternary stereocenter.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Cidan Lv, Xiangxiang Meng, Min Wang, Yan Zhang, Changwei Hu, Chan Kyung Kim, Zhishan Su
Summary: The mechanism and stereoselectivity of an asymmetric cyclopropanation reaction between 3-alkenyl-oxindole and sulfoxonium ylide catalyzed by a chiral N,N'-dioxide-Mg(II) complex were explored. The presence of N-protecting groups in the isatin enhanced the reactivity of the reactants, while steric effects of substituents in the chiral ligand played a crucial role in the selectivity of the reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Matthias Peeters, Jonathan Decaens, Alois Fuerstner
Summary: Chiral [BiRh]-paddlewheel complexes empowered by London dispersion enable the generation of (trifluoromethyl)furfurylidene metal complexes from a bench-stable triftosylhydrazone precursor. These complexes undergo asymmetric [2+1] cycloadditions, providing optically active trifluoromethylated cyclopropane or -cyclopropene derivatives, which are important building blocks for medicinal chemistry and difficult to obtain in optically active form.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Dong-Sheng Ji, Hui Liang, Kai-Xuan Yang, Zhi-Tao Feng, Yong-Chun Luo, Guo-Qiang Xu, Yucheng Gu, Peng-Fei Xu
Summary: A chemically divergent synthesis of beta-lactams and alpha-amino acid derivatives was achieved by using isothiourea (ITU) catalysis and switching solvents, demonstrating the versatility of this method.
Article
Chemistry, Organic
Guo-Shu Chen, Yu-Bo Fang, Zhi Ren, Xu Tian, Yun-Lin Liu
Summary: This study introduces a new reaction method, utilizing DABCO-catalyzed generation of carbonate anions to achieve selective reactions between isatin-derived MBH carbonates and 3-formylchromones, leading to spirocyclopentene oxindoles and spirocyclopentadiene 2-oxindoles. The approach also allows for the synthesis of highly functionalized bisoxindoles with tri- and tetra-substituted alkene groups, demonstrating the versatility of the catalytic system.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Review
Chemistry, Multidisciplinary
Hoorub Ahmad, Muhammad Bilal, Tahir Maqbool, Nasir Rasool, Syed Adnan Ali Shah, Zainul Amiruddin Zakaria
Summary: Asymmetric catalysis is a method to produce stereoisomeric molecules with a chiral catalyst. Copper, among transition metals, is cost-effective, abundant, and less toxic. This review focuses on asymmetric transformations in the last fifteen years.
JOURNAL OF SAUDI CHEMICAL SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Yubo Jiang, Ryan E. McNamee, Philip J. Smith, Ana Sozanschi, Zixuan Tong, Edward A. Anderson
Summary: Cascade reactions, also known as domino reactions, are a powerful means to construct multiple ring systems in a single step. This review discusses highlights in cascade polycyclizations applied to natural product syntheses over the last five years, including various processes such as pericyclic, ionic, metal-catalyzed, organocatalytic, and radical processes. Emphasis is placed on significant advancements in each field, such as photochemical and electrochemical methods, novel biomimetic routes, and enantioselective cascades.
CHEMICAL SOCIETY REVIEWS
(2021)
Article
Chemistry, Organic
Fuying Zhu, Yamei Lin
Summary: In this study, a low-metal iron-supported catalyst (Fe20/NC-Mg) was reported for the efficient synthesis of quinoxaline compounds, using water as a solvent and without additional bases. The synergistic effect of FeNx site and Mg (OH)2 nanorods in the catalyst played a key role in achieving high yields (82-91%) in 16 examples. The gram-level synthesis and reusability of the catalysts after four cycles demonstrated its industrial application potential.
Article
Chemistry, Organic
Mikhail Kozlov, Alexey Tyurin, Andrey Dmitrenok, Vyacheslav Rusak, Aleksander Fedorov, Igor Zavarzin, Yulia Volkova
Summary: This study presents a novel and practical synthesis method for phosphorus-substituted 1,3,4-thiadiazolines using phosphorylthioformic acid hydrazides and ketones. The protocol demonstrates operational simplicity, availability of reagents, and tolerance towards different functional groups.
Article
Chemistry, Organic
Jisna Jose, Thomas Mathew
Summary: 2-Cyclopentenone and its derivatives are highly esteemed synthetic intermediates with exceptional utility in organic synthesis. They are favored structural motifs in numerous pharmaceutical drugs and natural products, highlighting their significance. The review discusses the various methods used to synthesize cyclopentenones from 2016 to 2023.
