Regioselective, Mild Acylation of 2-Methylindole with Di- and Trialkoxycarbenium Tetrafluoroborates - A Simple Procedure for Deriving 3-Acyl-2-methyl-indoles and 3-Methoxycarbonyl-2-methylindole. Reactions of Electron-rich Heterocycles with Derivatives of Carboxylic Ortho Acids, VII.

Article abstract of DOI:10.1007/BF00816532

The regioselective acylation of 2-methylindole (2) with acyclic di- and trialkoxycarbenium tetrafluoroborates 1 produces, by way of the stable indolyl-alkoxycarbenium ions 4, the 3-acylated indoles 5a-5c, and the 3-methoxycarbonylindole 5d.The ambident electrophilic cations 1 all react as a¹-electrophiles with the very nucleophilic indole 2.In the reaction of 2 with trimethoxycarbenium tetrafluoroborate (2d) methylated products are formed additionally. - Keywords: 3-Acylated 2-methylindoles; Synthesis with di- and trialkoxycarbenium tetrafluoroborates