RSS-Feed abonnieren
DOI: 10.1055/a-1765-1615
From Ring-Expansion to Ring-Contraction: Synthesis of γ-Lactones from Cyclobutanols and Relative Stability of Five- and Six-Membered Endoperoxides toward Organic Bases
N. Jamey thanks the Ministère de l’Enseignement Superieur, de la Recherche et de l′Innovation (MESRI) for a PhD fellowship.
Abstract
Cyclobutanols undergo ring expansion with molecular oxygen in the presence of Co(acac)2 to afford 1,2-dioxane-hemiperoxyketals. In the course of acylation, we observed that endoperoxides rearranged into γ-lactone in the presence of triethylamine. Thus, a generalization of this ring contraction through a Kornblum–DeLaMare rearrangement is here reported. Application of this transformation to monosubstituted 1,2-dioxane derivatives also led to 1,4-ketoaldehydes, in proportions depending on the nature of the substituent. These same conditions applied to five-membered dioxolane analogues led to fragmentation instead, through a retro-aldol type process. This study emphasizes the difference of stability of 1,2-dioxane and 1,2-dioxolane against organic bases, 1,2-dioxolanes having proved to be particularly reactive whereas 1,2-dioxanes showed a relative tolerance under these conditions.
Key words
peroxides - ring contraction - ring-expansion - lactones - fragmentations - rearrangement - heterocyclesSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/a-1765-1615.
- Supporting Information
Publikationsverlauf
Eingereicht: 03. Dezember 2021
Angenommen nach Revision: 07. Februar 2022
Accepted Manuscript online:
07. Februar 2022
Artikel online veröffentlicht:
24. März 2022
© 2022. Thieme. All rights reserved
Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany
