Divergent Reactivity of Triaryldivinyl Ketones: Competing 4π and Putative 6π Electrocyclization Pathways.

Autor: Yadykov AV; N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation., Eremchenko AE; N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation.; D. I. Mendeleev University of Chemical Technology of Russia, 125047 Moscow, Russian Federation., Milosavljevic A; Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14611, United States., Frontier AJ; Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14611, United States., Shirinian VZ; N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation.
Jazyk: angličtina
Zdroj: The Journal of organic chemistry [J Org Chem] 2022 Nov 04; Vol. 87 (21), pp. 13643-13652. Date of Electronic Publication: 2022 Oct 11.
DOI: 10.1021/acs.joc.2c01294
Abstrakt: This work describes an acid-promoted cyclization of triaryldivinyl ketones containing a thiophene moiety in the α-position. Two cyclization pathways are accessible: one a 4π-Nazarov cyclization and the other we propose to proceed through a 6π electrocyclic mechanism. The relative proportion of products from these divergent pathways is affected by reaction conditions and steric bulk in the substrate. We present experimental and computational evidence that when using HCl in dioxane, the 4π-conrotatory electrocyclization is more favorable, whereas GaCl 3 in methylene chloride shifts the chemoselectivity toward a putative 6π-disrotatory electrocyclization. DFT calculations suggest that a complex interplay between kinetic and thermodynamic factors is implicated in the chemodivergent behavior.
Databáze: MEDLINE
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