A general and single-step access to polysubstituted 3-hydroxypyridine scaffolds via hetero-Diels-Alder (HDA) reactions between readily prepared 5-ethoxyoxazoles and dienophiles is reported. The HDA reaction, run in the presence of Nd(OTf)(3) at room temperature, was successfully applied to various 5-ethoxyoxazoles showing good functional group tolerance, and led to a straightforward process to obtain useful building-blocks.
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http://dx.doi.org/10.1039/c1cc16562c | DOI Listing |
Org Lett
January 2025
Institute of Next Generation Matter Transformation, College of Material Sciences Engineering at Huaqiao University, 668 Jimei Boulevard, Xiamen, Fujian 361021, China.
Domino cascade reactions, which can construct multiple bonds in one pot, are efficient methods to synthesize N-heterocycles and other useful skeletons. Herein, we report an expedient synthesis of polysubstituted benzo[][1,5]naphthyridine via Mn(III)-mediated C-C bond cleavage of cyclopropanols. These reactions were initiated by addition of β-carbonyl radicals, generated from cyclopropyl alcohols in the presence of Mn(III), to 2-(2-isocyanophenyl)acetonitriles to give quinolin-3-amines, which went through intramolecular cyclizations and dehydrogenation to give the final products.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Instrumentation Center, National Taiwan University, Taipei, 106, Taiwan.
A visible light photocatalytic cascade reaction was developed, involving sequential self-[2+2] photodimerization of benzoylacetones, De Mayo reaction, acetalization, and alkoxylation, yielding tetrahydrofurans with high stereoselectivity, three stereogenic centers, and two quaternary carbons, under mild conditions with a cycloaddition-rearrangement strategy. Given the significance of photoreaction and rearrangement in organic chemistry, this method provides a valuable approach for the synthesis of tetrahydrofurans.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemistry, Fudan University, 220 Handan Rd., Shanghai, 200433, China.
Atropisomers with multiple stereogenic axes have attracted much attention due to their increasing significance in the fields of natural products, chiral materials, and drug discoveries. However, the catalytic stereoselective construction of axially chiral ring scaffolds with more than two axes on a single benzene ring remains a challenging task. Herein, we present an efficient method for synthesizing triaxially chiral polysubstituted naphthalene scaffolds via sequential Ni(II)-catalyzed Diels-Alder reaction of isobenzofurans and TfOH-promoted dehydrative aromatization reaction.
View Article and Find Full Text PDFOrg Lett
December 2024
Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing 210095, P. R. China.
A series of 3-phosphonyl polysubstituted pyridine were first synthesized by photocatalysis, combining a phosphonyl radical cascade reaction, Boc deprotection, and aromatization. This strategy can avoid the difficulties of activating the C3-H bond on pyridine to synthesize 3-phosphonylpyridine under mild conditions. Furthermore, by constructing different enynes, we can achieve the metal-free modular synthesis of 3-phosphonyl polysubstituted pyridine, which will be transferred into a new type of phosphine ligand.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an 710021, P. R. China.
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