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Synlett 2024; 35(14): 1725-1727
DOI: 10.1055/s-0042-1751548
DOI: 10.1055/s-0042-1751548
letter
Regioselective Formation of Pyridines by Cycloaddition/Cycloreversion of 1,4-Oxazinone Precursors with Bisalkyne Substrates
Authors
This work was supported by the National Institutes of Health, General Medical Sciences (NIH R15GM107702 to J.R.S.).
Abstract
This study explores the merged cycloaddition/cycloreversion of a 1,4-oxazinone substrate and conjugated bisalkyne precursors. Good regioselectivity in the Diels–Alder operation is observed and pyridines bearing 3-alkynyl functionality are afforded following cycloreversion and extrusion of CO2. Examples with both symmetric and nonsymmetric bisalkyne substrates are included.
Supporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/s-0042-1751548.
- Supporting Information (PDF)
Publikationsverlauf
Eingereicht: 21. November 2023
Angenommen nach Revision: 13. Dezember 2023
Artikel online veröffentlicht:
18. Januar 2024
© 2024. Thieme. All rights reserved
Georg Thieme Verlag KG
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References and Notes
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- 7 General Experimental Conditions for Cycloaddition/Cycloreversion for all New Compounds An oven-dried vial was charged with oxazinone (1 equiv), a magnetic stir bar, and dissolved in PhMe (1 M). The alkyne substrate (1.0–2.0 equiv) was added, the vial was sealed with a Teflon cap and placed in a warm aluminum block set to 110 °C. The reaction was stirred with heating overnight (12–18 h), cooled to rt, and concentrated. The ratio of pyridine products was estimated based on 1H NMR analysis of the unpurified reaction mixture. The resulting residue was purified by flash column chromatography on silica gel.
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