Article
Chemistry, Organic
Jiru Shao, Caiyun An, Sunewang R. Wang
Summary: This study reports an easy method for synthesizing polysubstituted 2-pyrones from readily available 2-acylcyclopropane-1-aryl-1-carboxylates mediated by TfOH, with a key role played by the strongly donating 1-aryl group in directing the C-C bond cleavage of the donor-acceptor cyclopropane ring to form the 2-pyrone ring through lactonization.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Organic
Simon Kolb, Nils L. Ahlburg, Daniel B. Werz
Summary: A new electrochemical method has been described for the functionalization of donor-acceptor cyclopropanes and cyclobutanes with arenes using Friedel-Crafts-type reactivity. The catalyst-free strategy relies on direct anodic oxidation of strained carbocycles, leading to the formation of radical cations that act as electrophiles for the arylation reaction. Broad reaction scopes for cyclopropanes, cyclobutanes, and aromatic reaction partners are presented, along with a proposed electrolysis mechanism.
Article
Chemistry, Organic
Pan Tang, You -Yuan Wei, Long Wen, Hao-Jie Ma, Yi Yang, Yan Jiang
Summary: This article investigates the MgI2-catalyzed nucleophilic ring-opening reactions of donor-acceptor cyclopropanes with indoline-2-thiones as sulfur nucleophiles. Under mild reaction conditions, a series of functionalized gamma-indolylthio butyric acid derivatives are obtained in good to excellent yields. Additionally, the thioether functionalized ring-opening products can be transformed into sulfone and methionine analogues.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Florian Sachse, Christoph Schneider
Summary: A cooperative, one-pot approach has been developed for the in situ generation and subsequent cycloaddition of thioaldehydes and ortho-quinone methides under UV-A light and Brønsted acid catalysis, providing direct access to benzo[e][1,3]oxathiines in good to excellent yields and diastereoselectivity. Both electron-rich and electron-poor thioaldehydes can easily react with a wide range of ortho-quinone methides at ambient temperature in a short reaction time, producing a variety of S,O-heterocycles.
Article
Chemistry, Multidisciplinary
Guanghui An, Jianhui Liu
Summary: A synthetic methodology for a series of 2-thioimidazoline-4-ones was developed using trifluoromethanesulfonic acid and N,N'-dimethylethylenediamines in dichloromethane. The new compounds were characterized by various spectroscopic techniques and X-ray crystallography for further confirmation. High yields were obtained during the cyclization process.
Article
Chemistry, Applied
Agathe C. A. D'Hollander, Eugenie Romero, Kamsana Vijayakumar, Camille Le Houerou, Pascal Retailleau, Robert H. Dodd, Bogdan I. Iorga, Kevin Cariou
Summary: In this study, it was found that ynamides can undergo a [3+2] cycloaddition with 2-azaallyl anions under basic conditions and heat, resulting in the formation of nitrogen-rich heterocycles. The reaction generally shows excellent diastereoselectivity, favoring the cis adduct. Deuteration experiments and DFT calculations were used to rationalize the regio- and stereoselectivity of the process as well as the formation of side products.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Manman Sun, Jing Gui, Rong Zhong, Haijian Wu, Saimei Liu, Jinshan Li, Jianguo Yang, Zhiming Wang
Summary: A TfOH-catalyzed direct Michael addition and cascade cyclization reactions of azadienes with unactivated ketones have been developed, providing a divergent approach to 2,3-disubstituted benzofurans and benzofuro[3,2-b]pyridines. This method utilizes the weak nucleophilicity of unactivated ketones and controls the catalyst acidity as a key parameter. The use of commercial ketones and mild reaction conditions also offer synthetic and environmentally benign advantages.
Article
Chemistry, Multidisciplinary
Zebediah C. Girvin, Laura F. Cotter, Hyung Yoon, Steven J. Chapman, James M. Mayer, Tehshik P. Yoon, Scott J. Miller
Summary: High selectivity in photochemical reactions can be achieved by controlling the transition state.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Thomas Rigotti, Daniel P. Schwinger, Raphaela Grassl, Christian Jandl, Thorsten Bach
Summary: This study presents a highly enantioselective crossed [2+2] photocycloaddition reaction that can produce intriguing bridged skeletons.
Article
Chemistry, Applied
Baofu Zhu, Wen Li, Haixin Chen, Minjian Wu, Jijing Hu, Hua Cao, Xiang Liu
Summary: A mechanochemical Cu-catalyzed [3 + 2] cycloaddition of azinium-N-imines with nitriles was reported under solventless grinding conditions. Various 1,2,4-triazolos derivatives were obtained in high yields. The developed protocol offers advantages in functional-group compatibility, scalability, and shorter reaction time.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Ming Bao, Karlos Lopez, Raj Gurung, Hadi Arman, Michael P. Doyle
Summary: A highly enantioselective synthesis of chiral dihydro-3H-carbazole-2-carboxylate derivatives is achieved via a one-pot cascade reaction catalyzed by nickel(II) perchlorate hexahydrate and scandium(III) trifluoromethanesulfonate. The reaction proceeds under mild conditions and provides the desired products in high yields and enantioretention. Furthermore, these dihydro-3H-carbazole-2-carboxylates can be transformed into decarboxylated compounds through hydrolysis and decarboxylation under unexpectedly mild reaction conditions, giving moderate yields with high retention of enantiomeric purity.
Article
Chemistry, Physical
Ming Bao, Karlos Lopez, Raj Gurung, Hadi Arman, Michael P. Doyle
Summary: A highly enantioselective synthesis of chiral dihydro-3H-carbazole-2-carboxylate derivatives is achieved via a one-pot cyclopentannulation-rearrangement cascade reaction. The reaction is catalyzed by nickel(II) perchlorate hexahydrate and scandium(III) trifluoromethanesulfonate, and involves the use of 3-methylindole and non-racemic donor-acceptor cyclopropanes. The resulting products show high yields and enantioretention under mild reaction conditions, and further transformation into decarboxylated compounds can be achieved with moderate yields and high enantiomeric purity.
Article
Chemistry, Organic
Katarina Stefkova, Michael G. Guerzoni, Yara van Ingen, Emma Richards, Rebecca L. Melen
Summary: Here, a mild, transition-metal-free, highly diastereoselective Lewis acid catalyzed methodology for the synthesis of isoxazolidine-based diazo compounds from the reaction between vinyldiazo esters and nitrones is reported. Interestingly, the diastereoselectivity of the isoxazolidine products is found to be contrasting to previous metal-catalyzed reactions. Furthermore, the same catalyst can be used with enol diazo esters, leading to the formation of Mukaiyama-Mannich products. These diazo products can be further functionalized to generate benzo[b]azepine and pyrrolidinone derivatives.
Article
Biochemistry & Molecular Biology
Nicolai A. Aksenov, Alexander V. Aksenov, Igor A. Kurenkov, Nikita K. Kirillov, Dmitrii A. Aksenov, Nikolai A. Arutiunov, Daria S. Aksenova, Michael Rubin
Summary: A highly efficient one-pot method for the synthesis of biologically active 2-(3-oxoindolin-2-yl)acetonitriles has been designed, which involves a base-assisted aldol reaction followed by hydrocyanation, triggering an unusual reductive cyclization reaction.
Article
Chemistry, Organic
Mokhamatam Sudheer, Chinthu Joginarayana Rao, Venkateswara Rao Battula
Summary: The regioselective enone synthesis from intermolecular coupling of aldehydes and alkynes has been developed using triflic acid as the catalyst. This reaction is efficient, effective, simple and mild, with diverse substrate scope. Both aryl and aliphatic aldehydes can smoothly participate in the reaction and exclusively provide trans product.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
