An efficient synthesis of deoxy-lambertellols was reported through a highly chemo- and diastereoselective intermolecular Diels-Alder cycloaddition between trans-1,2-disiloxybenzocyclobutenes and 2-methylprotoanemonine. Such transformation with δ-substituted γ-alkylidenebutenolides, to prepare new analogues of these tricyclic spirolactones, which would be very difficult to prepare by other ways, was also studied.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1039/c0ob00448k | DOI Listing |
Org Lett
January 2025
Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan.
Multiple Diels-Alder reactions are a powerful method to construct large asymmetric scaffolds, but these reactions often produce numerous isomers. We now report a triple Diels-Alder reaction between a cyclic furan trimer and -substituted maleimides, achieving selective synthesis of a single asymmetric tris-adduct. The stereoselectivity of cycloaddition to π-extended furan derivatives was clarified by the experimental analysis of intermediates and theoretical calculations.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/Maria Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain.
Both silicon and carbon are elements located in group 14 on the periodic table. Despite some similarities between these two elements, differences in reactivity are important, and whereas carbon is a central element in all known forms of life, silicon is barely found in biological systems. Here, we investigate the Diels-Alder cycloaddition reaction of cyclopentadiene (CP) and cyclopentasildiene (CP) with fullerenes C, Li@C, Si, and Li@Si using density functional theory methods.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China. Electronic address:
The inverse electron demand Diels-Alder (IEDDA) cycloaddition between tetrazines and strained dienophiles is recognized as a fast and specific reaction. The integrating tetrazines and strained dienophiles onto the backbone of polysaccharides yield appropriate water-soluble precursors for IEDDA cycloaddition. Due to the high specificity of the IEDDA reaction and its outstanding cytocompatibility, a range of cargos (live cells, peptides and pharmaceuticals) can be effectively encapsulated in polysaccharide solutions throughout the hydrogel formation.
View Article and Find Full Text PDFBeilstein J Org Chem
January 2025
Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell'Insubria, Via Valleggio 9, 22100, Como, Italy.
This review reports the achievements in copper(II) triflate-catalyzed processes concerning the multicomponent reactions, applied to the synthesis of acyclic and cyclic compounds. In particular, for the heteropolycyclic systems mechanistic insights were outlined as well as cycloaddition and aza-Diels-Alder reactions were included. These strategies have gained attention due to their highly atom- and step-economy, one-step multi-bond forming, mild reaction conditions, low cost and easy handling.
View Article and Find Full Text PDFChemphyschem
January 2025
University of Namur, Department of Chemistry, Rue de Bruxelles, 61, 5000, Namur, BELGIUM.
The [4+2] Diels-Alder cycloaddition reaction between 2,5-DMF (1) and ethylene derivatives (2a-h) activated by electron-withdrawing groups has been studied at the density functional theory levels using a panoply of tools to unravel the reaction mechanisms. From the analysis of the reactivity indices, 2a-h behave as electrophiles while 1 as nucleophile, and the activation of the double bond of ethylene increases its electrophilicity, which is accompanied by an enhancement of the polarity of the reaction. The activation Gibbs free energy decreases linearly as a function of this increase of polarity, as estimated by the electrophilicity difference between the reactants.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!