Lewis Acid Mediated Addition of Indoles and Alcohols to Tetronic Acid and Tetramic Acids

Abstract

The electrophilic substitution of indoles with tetronic acid and N-acetyltetramic acid mediated by BF₃·OEt₂ was investigated. This strategy allowed for the preparation of nine indole-substituted furan-2-ones (indolyl-γ-lactones) and 3-pyrrolin-2-ones (indolyl-γ-lactams) and is more straightforward than previously reported synthetic methods. During the course of our investigation, we also discovered a facile synthesis of tetronates and a tetramate via a BF₃-mediated addition of alcohols to tetronic acid and N-acetyltetramic acid, respectively.

Key words

lactams - lactones - indoles - heterocycles - cycloadditions

• References and Notes


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