The electrophilic substitution of indoles with tetronic acid and N-acetyltetramic acidmediated 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