By exploiting the unique reactivity of ethynyl-phosphonites we obtain novel P(V)-containing five-membered heterocycles via (3+2)-cyclization reactions with aldehydes or cycloaliphatic thioketones in satisfactory to excellent yields. Whereas reactions with thioketones to yield 1,3-thiaphospholes-3-oxides occur smoothly at room temperature with equimolar amounts of the starting materials in absence of any catalyst, the analogous conversions with aldehydes to generate 3-oxides of 1,3-oxaphospholes require addition of triethylamine as a base. We postulate a step-wise (3+2)-cyclization mechanism for the formation of the 1,3-thiaphosphole ring based on DFT quantum chemical calculations. With this study, we introduce new cyclization reactions originating from unsaturated phosphonites as central synthetic building blocks to yield previously inaccessible stable phosphorus-containing heterocycles with unexplored potential for the molecular sciences.
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http://dx.doi.org/10.1002/chem.202300806 | DOI Listing |
Chemistry
January 2025
College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China.
J Org Chem
November 2024
Department of Chemistry, Zhejiang University, Hangzhou 310058, China.
A novel asymmetric [3 + 2] cyclization of α-indolyl propargylic alcohols with 3-alkyl-1H-indoles via chiral phosphoric acid catalysis has been established. This strategy allowed the synthesis of chiral α-indolyl pyrrolo[1,2-a]indole derivatives with high yields (up to 91%) and excellent enantioselectivities (up to 99% ee), facilitating both the reaction activity and enantioselectivity by using the solvent of CHCFCl. Significantly, this protocol will provide an effective synthetic approach for constructing enantioenriched α-indolyl pyrrolo[1,2-a]indole cores of antimalarial natural product isoborreverine analogues.
View Article and Find Full Text PDFOrg Lett
November 2024
State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830046, Xinjiang, People's Republic of China.
A Cu-catalyzed [3 + 2] cyclization of amidines with trifluoromethyldiazo compounds is described. The reaction affords 5-fluoroimidazoles in good yields by cleaving dual C-F bonds in a CF group. Using 2-aminoazo heterocycles as the substrates, various annelated imidazoles containing a fluorine atom were also constructed by this method without changing the conditions.
View Article and Find Full Text PDFJ Org Chem
September 2024
Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Material Science, Hebei University, Baoding, Hebei 071002, PR China.
This study presents the synthesis of novel naphthofurano-iminosugars () using 2,3--isopropylidene D-ribose tosylate (), anilines (), and 1,4-benzoquinone () as starting materials through key iminium ion/enamine intermediates via [3 + 2] cyclization reactions at room temperature. The reaction has unique regioselectivity and stereoselectivity with moderate to excellent yields. The adaptability of this method has been demonstrated using various substituted anilines, on which both electron-donating and electron-withdrawing groups were well employed in the reactions.
View Article and Find Full Text PDFJ Mol Model
August 2024
The Fifth Affiliated Hospital, Guangdong Province NMPA and State Key Laboratory, The School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou, 511436, P. R. China.
Context: The challenge of activating inert allyl monomers for polymerization has persisted, prompting our proposal of the photo-driven radical mediated [3 + 2] cyclization reaction (PRMC). This innovative approach significantly expedites the homopolymerization of multi-allyl monomers, enabling the synthesis of embolic microspheres for hepatocellular carcinoma interventions. PRMC involves allyl monomers to form allylic radicals and then radicals participating in a cycloaddition reaction with unsaturated olefins as radicalophiles to form cyclopentane-based radical products.
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