Copper-catalyzed 6-endo cyclization of N-propargylic β-enaminocarbonyls was developed for the synthesis of oxidation-labile 1,6-dihydropyridines. This synthetic method allows flexible and regio-defined assembly of various substituents at the N1, C2, C3, C4, and C6 positions of 1,6-dihydropyridines under mild conditions.
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http://dx.doi.org/10.1039/c5ob00356c | DOI Listing |
J Org Chem
January 2025
School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, China.
A novel regioselective manganese(III)-mediated radical cascade cyclization of N-propargyl enamides with various H-phosphine oxides, H-phosphinates and H-phosphonates was developed. Mechanistic studies show that the reaction is mainly composed of the selective addition of phosphonyl radical to C≡C bond and the intramolecular 6--trig cyclization of vinyl radical. Utilizing this protocol, we successfully synthesized a diverse range of 3-phosphorylpyridines in high efficiency with good functional group compatibility and simple operation.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an, 710032, China.
An efficient synthesis of continuously substituted quinoline derivatives palladium-catalyzed intramolecular 6- imidoylative cyclization of -alkenyl aryl isocyanides with (hetero)aryl halides or vinylic triflates has been developed. The reaction proceeds through the concerted metalation-deprotonation (CMD) mechanism by activation of a vinyl C-H bond with imidoylpalladium assisted by the carboxylate.
View Article and Find Full Text PDFJ Org Chem
January 2025
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, P. R. China.
An effective and economical copper-catalyzed approach for the synthesis of phosphorylated 1-isochromenes is reported. This method is the first example of focus on ketone phosphonylation to establish a C-P bond and 6-- cyclization to construct a C-O bond between aryl- and alkyl-substituted alkynylketones and H-phosphinate esters, H-phosphites, and H-phosphine oxides, resulting in chemo- and regioselective phosphorylated 1-isochromenes with moderate to excellent yields under smooth reaction conditions.
View Article and Find Full Text PDFCommun Chem
November 2024
College of Pharmacy and Medicinal Research Center (MRC) Chungbuk National University, Cheongju, 28160, Republic of Korea.
Pyridazine derivatives hold significant interest due to their broad applications in pharmaceuticals and materials science, where they serve as valuable scaffolds for bioactive compounds and functional materials. Here, we report a formal [4 + 2] reaction for the synthesis of 5'-sulfonyl-4'-aryl-3-cyano substituted pyridazine compounds from the reaction between vinylogous enaminonitriles and sulfonyl hydrazides. The key features of our pyridazine synthesis include the transamidation of vinylogous enaminonitriles with sulfonyl hydrazide, radical sulfonylation of the resulting intermediate, and subsequent 6-endo-trig radical cyclization.
View Article and Find Full Text PDFOrg Lett
November 2024
School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China.
An efficient FLP-mediated cycloisomerization is described, providing easy access to quinolinium and chromenylium derivatives by treatment of readily available propargylanilines and aryl propargyl ethers with Lewis acidic boranes, respectively. The reaction proceeds via a 6--dig cyclization/dehydrogenation sequence. The heteroatom functions serve as Lewis bases in combination with Lewis acidic boranes to effect synergistic activation of an alkynyl triple bond and a C-H bond.
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