The "cesium effect" magnified: exceptional chemoselectivity in cesium ion mediated nucleophilic reactions.

Autor:	Biswas S; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., Hughes WB; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., De Angelis L; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., Haug GC; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., Trevino R; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., Fremin SO; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., Arman HD; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., Larionov OV; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu., Doyle MP; Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA oleg.larionov@utsa.edu michael.doyle@utsa.edu.
Jazyk:	angličtina
Zdroj:	Chemical science [Chem Sci] 2024 Mar 06; Vol. 15 (14), pp. 5277-5283. Date of Electronic Publication: 2024 Mar 06 (Print Publication: 2024).
DOI:	10.1039/d4sc00316k
Abstrakt:	Chemodivergent construction of structurally distinct heterocycles from the same precursors by adjusting specific reaction parameters is an emergent area of organic synthesis; yet, understanding of the processes that underpin the reaction divergence is lacking, preventing the development of new synthetic methods by systematically harnessing key mechanistic effects. We describe herein cesium carbonate-promoted oxadiaza excision cross-coupling reactions of β-ketoesters with 1,2,3-triazine 1-oxides that form pyridones in good to high yields, instead of the sole formation of pyridines when the same reaction is performed in the presence of other alkali metal carbonates or organic bases. The reaction can be further extended to the construction of synthetically challenging pyridylpyridones. A computational study comparing the effect of cesium and sodium ions in the oxadiaza excision cross-coupling reactions reveals that the cesium-coordinated species changes the reaction preference from attack at the ketone carbonyl to attack at the ester carbon due to metal ion-specific transition state conformational accommodation, revealing a previously unexplored role of cesium ions that may facilitate the development of chemodivergent approaches to other heterocyclic systems. Competing Interests: There are no conflicts to declare. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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