Synthesis of Cyclic Diglycerols: The Utility of the BF₃·OEt₂-Mediated Intramolecular Epoxide Ring-Opening Reaction for the Cyclic Polyglycerol Synthesis

Abstract

We report the synthesis of cyclic diglycerols, which are the smallest repeating units in polyglycerols. Linear diglycerol epoxy alcohols are treated with a catalytic amount of boron trifluoride–diethyl ether complex (BF₃·OEt₂) in highly dilute dichloromethane (CH₂Cl₂) to give the corresponding 1,4-dioxepane- and 1,4-dioxane-type cyclic diglycerols in high yields as single structural isomers. The structures of the cyclic products are determined by 1D and 2D NMR spectral analysis. The observed results indicate that the cyclizations are consistent with Baldwin’s rules. The synthesized cyclic diglycerols can serve as standards for further studies.

Key words

cyclic diglycerols - epoxide ring opening - cyclization - regioselectivity - substitution

Publication History

Received: 02 September 2024

Accepted after revision: 03 December 2024

Accepted Manuscript online:
03 December 2024

Article published online:
09 January 2025

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