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Palladium-catalyzed decarboxylation of 5-methylene-1,3-oxazinan-2-ones and 5-methylene-1,3-dioxan-2-ones to generate aza-π-allylpalladium and oxa-π-allylpalladium 1,4-dipoles for [4 + 2] cycloaddition reaction with 1,3,5-triazinanes was developed, affording a wide range of hexahydropyrimidine and 1,3-oxazinane derivatives in good to excellent yields (up to 99%). The acyclic sulfonamido-substituted allylic carbonates as aza-π-allylpalladium 1,4-dipole precursors also apply to the developed synthesized strategy, achieving the synthesis of hexahydropyrimidines. Moreover, the in situ-generated aza-π-allylpalladium 1,4-dipoles undergoing dimeric [4 + 4] cycloaddition were also demonstrated by the construction of 1,5-diazocane derivatives.
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http://dx.doi.org/10.1021/acs.joc.4c00128 | DOI Listing |
Org Lett
September 2025
School of Pharmacy and Food Engineering, Wuyi University, Jiangmen 529090, P. R. China.
3-Fluoropyrroles are privileged scaffolds in pharmaceutical and agrochemical applications, yet their synthesis remains challenging. Herein, we report a palladium(0)-catalyzed [4+1] cycloaddition/dehydration strategy for the efficient construction of 3-fluoropyrroles from readily available 3,3-difluoropent-4-en-2-ones and primary amines. This transformation proceeds via C-F bond activation to generate a key π-allyl-Pd(II) intermediate, followed by intramolecular addition/dehydration to furnish the heterocyclic core.
View Article and Find Full Text PDFChem Asian J
August 2025
Department of Chemistry, National Institute of Technology Tiruchirappalli, Tiruchirappalli, Tamil Nadu, 620015, India.
Pd-catalyzed straight forward [3+2] cycloaddition reaction between spirovinylcyclopropyl-2-oxindole and coumarin/bioisosteres is demonstrated. The resultant products spirooxindolyl-cyclopentane[c]chromanones and structural analogues are obtained in up to 97% yields and > 99:1 dr. The target spirooxindole-cyclopentane architectures with four contiguous stereocenters with high diastereocontrol is differentially influenced by inexpensive 2,2'-bipyridyl ligand and greener solvent EtOH.
View Article and Find Full Text PDFOrg Biomol Chem
August 2025
Institute of Pharmaceutical Science and Technology, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, 18 Chaowang Road, Gongshu District, Hangzhou City, Zhejiang Province, China.
A palladium-catalyzed [3 + 2] cycloaddition reaction of vinyl methylene cyclic carbonates with pyrrolidinones was developed. This protocol demonstrates remarkable versatility, enabling the facile construction of diverse [5,5]-spirolactam scaffolds in excellent yields with outstanding diastereoselectivity. The synthetic utility of this protocol was further demonstrated through productive transformations of the resulting spirolactam products, highlighting their potential as valuable intermediates for complex molecule synthesis.
View Article and Find Full Text PDFJ Org Chem
September 2025
School of Pharmacy, Changzhou University, Changzhou, Jiangsu Province 213164, China.
Palladium-catalyzed and ligand-controlled cycloaddition of ()-β-trifluoromethylated enones has been described, providing powerful synthetic strategies for two α-CF-substituted O-heterocycles, tetrahydro-2-pyrans and 5-oxaspiro[2.4]heptanes. The readily available substrates bearing various functional groups have shown variable product chemoselectivities.
View Article and Find Full Text PDFJ Org Chem
August 2025
Department of Chemistry, China Agricultural University, Beijing 100193, P. R. China.
In this paper, we reported a palladium-catalyzed formal (4 + 1) cycloaddition reaction between amido-tethered allylic carbonates and sulfur ylides. The reaction worked well to provide γ-lactam compounds in satisfactory yields and displayed good compatibility to a wide range of functional groups. The synthetic value of the reaction was demonstrated through scale-up reaction and further transformation.
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