Cyclopolymerization is a powerful method for synthesizing polyacetylenes containing four- to seven-membered rings. However, the structure of the repeat unit only consists of mono-cycloalkene due to the single cyclization of diyne monomers. Herein, we demonstrate a novel cascade cyclopolymerization to synthesize polyacetylenes containing fused bicyclic rings from triyne monomers containing bulky dendrons via sequential cascade ring-closing metathesis. These dendrons provided solubility and stability to the rigid bicyclic polyacetylene backbone. In addition, we controlled the regioselectivity of the catalyst approach by altering its structure and synthesized polymers containing fused bicyclo[4,3,0] or [4,4,0] rings with high molecular weights of up to 120 kg mol . Interestingly, the resulting polymers showed narrower band gaps (down to 1.6 eV) than polymers with mono-cycloalkene repeat units due to the planarization of the conjugated segment resulting from the fused bicyclic structure.
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http://dx.doi.org/10.1002/anie.202210244 | DOI Listing |
J Org Chem
January 2025
Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos. Av. Universidad 1001, 62209 Cuernavaca, Morelos, Mexico.
Phosphonic analogs of octahydroisoindole-1-carboxylic acids are bicyclic proline derivatives of interest in drug design and enzymatic mechanism studies. Here we report the stereoselective synthesis of the - and -fused octahydroisoindole system using oxazoloisoindolone lactam and 1,2-cyclohexanedicarboxylic anhydride as advanced chiral precursors, respectively, yielding enantiopure octahydroisoindolone intermediates with the desired stereochemistry at the ring junction. Finally, using these intermediates, the target (1,3a,7a)- and (1,3a,7a)-octahydroisoindole-1-phosphonic acids and their enantiomers were obtained with complete stereocontrol via highly diastereoselective addition of trimethyl phosphite to chiral -acyliminium ions as the key step.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States.
Nucleophilic substitution reactions of C-2-acyloxy furanosyl acetals can be highly diastereoselective. We here show that the presence of a less electron-donating -nitrobenzoyloxy group at C-2 of a furanosyl acetal can be of use to control the 1,2- stereoselectivity of acetal substitution reactions with higher stereoselectivity than the analogue with the more electron-donating benzoyloxy group, just as what was observed in the pyranosyl system. Computational results support a reaction manifold involving both open oxocarbenium ions and -dioxolenium ions to provide the 1,2- and 1,2- products.
View Article and Find Full Text PDFNat Commun
December 2024
National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, College of Chemistry, Central China Normal University, Wuhan, P.R. China.
Skeleton editing for heteroarenes, especially pyrazoles, is challenging and remains scarce because these non-strained aromatics exhibit inert reactivities, making them relatively inactive for performing a dearomatization/cleavage sequence. Here, we disclose a cycloaddition-induced scaffold hopping of 5-hydroxypyrazoles to access the pyrazolopyridopyridazin-6-one skeleton through a single-operation protocol. By converting a five-membered aza-arene into a five-unit spine of a 6/6 fused-bicyclic, this work unlocks a ring-opening reactivity of the pyrazole core that involves a formal C = N bond cleavage while retaining the highly reactive N-N bond in the resulting product.
View Article and Find Full Text PDFPhytochemistry
April 2025
Shanghai Frontiers Science Center of Drug Target Identification and Delivery, School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Pharmacy, Fudan University, Shanghai, 201203, China. Electronic address:
As a both edible and medicinal plant, Hypericum patulum (Hypericaceae) is used as a natural herbal tea, scented tea, and folk medicine. In this study, eight undescribed bicyclic polyprenylated acylphloroglucinol-related meroterpenoids named hyperpatins A-H, along with eight known ones, were isolated from this plant. Their structures were elucidated on the basis of spectroscopic techniques, chemical method, X-ray crystallographic experiments, and electronic circular dichroism analyses.
View Article and Find Full Text PDFEur J Med Chem
February 2025
Department of Medicinal Chemistry, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran. Electronic address:
Over the past two decades, small molecules bearing [5,6]-bicyclic nitrogen-containing cores have emerged as one of the most extensively studied structures for the development of selective c-MET kinase inhibitors. Structure-activity relationship (SAR) studies have demonstrated that modifying these cores can significantly impact the biological properties of c-MET inhibitors, including safety/toxicity, potency, and metabolic stability. For example, although c-MET kinase inhibitors containing the [1,2,4]triazolo[4,3-b][1,2,4]triazine scaffold (core P) exhibit high inhibitory potency, they often face challenges due to metabolic stability defects.
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