Coupling of alkynyl moieties to heterocyclic rings, without using transition metals, can be easily performed by the reaction of aryl or heteroaryl sulfonylacetylenes with heteroaryl-Li compounds or their corresponding less reactive magnesium derivatives.
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http://dx.doi.org/10.1039/c4cc07574a | DOI Listing |
In sharp contrast to the intuitive modulation by the electronic effect, the [4 + 1] annulation reaction between α-substituted conjugated enones and ylides has been reliably controlled by the match of the α-substituent and the ylide in steric hindrance, providing a straightforward and efficient method for valuable 4-cyano, 4-alkynyl, 4-vinyl, and 4-aryl 2,3-dihydrofurans.
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December 2024
School of Chemistry, University College Dublin, Dublin 4, Ireland.
We report a new and straightforward route toward substituted benzo[]fluorenes via the direct photochemical conversion of alkynylated chalcones. This transformation exploits a high-power light-emitting diode emitting ultraviolet A light to enable the rapid formation of the target products ( = 5 min). A continuous flow approach thereby facilitates reproducibility and scalability, granting streamlined access to these important scaffolds and their derivatives.
View Article and Find Full Text PDFOrg Lett
November 2024
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
An intramolecular iodine(III)-mediated keto-oximation of -alkynyl hydroxylamines offers rapid and straightforward access to 3-acyl Δ-isoxazolines and 1,2-oxazines. This approach features mild, metal-free, and aerobic reaction conditions with good functional group tolerance. Moreover, the synthetic utility of this method is demonstrated by the synthesis of unique structural motifs such as isoxazolidine, 3-vinyl isoxazoline, and 2,5-diphenylpyrazine derivatives by the conversion of 3-acyl Δ-isoxazolines, thereby showcasing its efficiency and applicability in synthetic chemistry.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2024
Department of Chemistry, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 300044, Taiwan.
Chem Commun (Camb)
August 2024
School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
Herein, a straightforward method for rapid access to all-carbon tertrasubstituted alkenes bearing alkyl, aryl and alkynyl groups is established palladium-catalyzed three-component cross-coupling reaction of internal alkynes, haloalkynes and arylboronic acids. This protocol is characterized by a broad substrate scope and excellent chemo- and regioselectivities. The dual beneficial roles of silver salts in activating haloalkynes and inhibiting bromoalkynylation have been demonstrated by serving as both the Lewis acid and halide scavenger.
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