A base-mediated annulation of 2-nitrobenzothiophenes with naphthols was realized for the synthesis of hitherto unknown class of heteroacenes, namely benzothieno[2,3-]naphthofurans. By using naphthols with a hydroxyl group positioned at 1st or 2nd position, we could synthesize two positional isomers, benzothieno[2,3-]naphtho[2,1-]furans or benzothieno[2,3-]naphtho[2,3-]furans. The annulation was found to be general with a range of substituted 2-nitrobenzothiophenes and naphthols. This heteroannulation of benzothiophene was extended using a range of phenols affording the corresponding benzothieno[2,3-]benzofurans in moderate yields. The basic photophysical properties of these heteroacenes were evaluated, and we also demonstrated the applicability of this annulation on the gram scale.
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http://dx.doi.org/10.1021/acs.joc.2c00645 | DOI Listing |
Molecules
December 2024
School of Material Science and Engineering, Dalian Jiaotong University, Dalian 116028, China.
An effective method for the construction of functionalized indolizines has been developed in which β,β-difluoro peroxides act as novel C2-building blocks to implement [3+2] annulation with pyridinium ylides under base-mediated conditions. With this protocol, a broad range of multisubstituted indolizines were prepared in moderate to good yields under mild conditions, and many useful functional groups were tolerated.
View Article and Find Full Text PDFJ Org Chem
November 2024
College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.
Org Lett
September 2024
State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830046, Xinjiang, P. R. China.
A base-mediated regioselective [3 + 3] annulation of alkylidene malononitriles with trifluoromethyl alkenes was described. The reaction proceeds through sequential intermolecular S2' and intramolecular SV-type cyclization by cleaving dual C-F bonds in a trifluoromethyl group, which discriminate multiple carbon-nucleophilic sites using a single base. Various bicycles bearing a monofluorocyclohexene motif were assembled from readily available starting materials under mild conditions via a one-pot cascade approach.
View Article and Find Full Text PDFOrg Biomol Chem
August 2024
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100040, People's Republic of China.
We introduce, for the first time, an inorganic base-mediated cyclization and auto-oxidation of bisallenones/bisalkynones. This reaction is realized under mild conditions through precise control of the base and atmosphere, providing a wide range of structurally diverse fused-pyran derivatives with moderate to excellent yields. Utilizing KOH as the initiator under a nitrogen atmosphere, a series of novel cyclohexane-fused pyran derivatives was obtained as the primary product.
View Article and Find Full Text PDFOrg Biomol Chem
July 2024
Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613 401, Tamil Nadu, India.
A highly efficient and innovative method involving base-mediated oxidative annulation between 2-naphthols and phenylglyoxal monohydrate under visible light irradiation has been successfully developed. This method leads to the formation of oxygen-containing heterocyclic compounds, particularly hydroxy-naphthofuranone derivatives, encompassing a unique quaternary carbon center. An X-ray diffraction study has unambiguously confirmed the structure of one such derivative.
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