Cooperative photoredox- and nickel-catalyzed alkylative cyclization reactions of iodoalkynes with 4-alkyl-1,4-dihydropyridines as alkylation reagents under visible light irradiation have been achieved to afford the corresponding alkylated cyclopentylidenes in good to high yields. Introduction of substituents at the propargylic position of iodoalkynes has led to the stereoselective formation of -isomers. The present reaction system provides a novel synthetic method for alkylative cyclization reactions of both terminal and internal alkynes with cooperative photoredox and nickel catalysis.
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http://dx.doi.org/10.1021/acs.joc.1c01018 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
IISER Kolkata: Indian Institute of Science Education and Research Kolkata, Department of Chemical Sciences, Mohanpur, 741246, Nadia, INDIA.
Chiral allyl amines are important structural components in natural products, pharmaceuticals, and chiral catalysts. Herein, we report a cobalt-catalyzed enantioselective reductive coupling of imines with internal alkynes to synthesize chiral allyl amines. The reaction is catalyzed by a cobalt complex derived from commercially available bisphosphine ligand utilizing zinc as the electron donor.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China.
A visible-light-induced deoxygenative alkylation/cyclization of acrylamides with alcohols activated by CS has been developed by using xanthate salts as alkyl radical precursors in the presence of tricyclohexylphosphine. It proceeds through a tandem radical addition/cyclization process, and this protocol provides a reliable and practical approach to building the skeleton of 3,3-disubstituted oxindoles in moderate to good yields. Notable features of this reaction include readily available starting reagents, broad substrate scope and mild reaction conditions.
View Article and Find Full Text PDFPharmaceuticals (Basel)
December 2024
Department of Chemistry, Faculty of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia.
Background: Recently, pyrido[2,3-] pyrimidine, triazolopyrimidine, thiazolopyrimidine, quinoline, and pyrazole derivatives have gained attention due to their diverse biological activities, including antimicrobial, antioxidant, antitubercular, antitumor, anti-inflammatory, and antiviral effects.
Objective: The synthesis of new heterocyclic compounds including 5-quinoline-pyrido[2,3-] pyrimidinone (-, , -), 6-quinoline-pyrido[2,3-]thiazolo[3,2-]pyrimidinone (, , -), 1,2,4-triazole-6-quinoline-pyrido[2,3-]thiazolo[3,2-]pyrimidinone (-), and pyrido[2,3-]thiazolo[3,2-]pyrimidine-ethyl-(pyridine)-9-thiaazabenzo[]azulenone () derivatives was performed with high yields while evaluating antimicrobial activities.
Methods: A new series of quinoline-pyrido[2,3-]thiazolo[3,2-]pyrimidine derivatives were prepared using a modern style and advanced technology, resulting in high yields of these new compounds.
J Org Chem
January 2025
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
The photoacid-catalyzed synthesis of 2-deoxy glycosides is presented using stable glycosyl -[1-(-MeO-Phenyl)vinyl]benzoate (PMPVB) donors and employing the eosin Y and diphenyl disulfide (PhSSPh) catalytic system in the presence of blue LED lights. The remote activation of the alkene functionality under the photoacid catalysis followed by a 5-- cyclization led to the generation of oxocarbenium ions that were trapped to provide the glycosylated products in excellent yields and decent selectivities under mild conditions. This method is also useful for the photoacid-catalyzed synthesis of -methoxybenzyl-alkyl ethers.
View Article and Find Full Text PDFChemistry
January 2025
Zelinsky Institute of Organic Chemistry of the Russian Academy of Science, Laboratory for Studies of Homolytic Reactions, Leninsky prospekt 47, 119991, Moscow, RUSSIAN FEDERATION.
The electrochemically mediated cyanation/annulation process with in situ cyanide ion generation from NH4SCN and multi-step oxidative construction of CN-functionalized heterocycles from easily available α-amino esters and pyridine-2-carbaldehydes has been discovered. Depending on the nature of the α-amino ester, 1-cyano-imidazo[1,5-a]pyridine-3-carboxylates, 3-alkyl- and 3-aryl-imidazo[1,5-a]pyridines-1-carbonitriles, and the first reported 4-oxo-4H-pyrido[1,2-a]pyrazine-1-carbonitriles were obtained. The electrosynthesis is carried out in an undivided electrochemical cell under constant current conditions.
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