ZrOCl2·8H2O as a highly efficient and the moisture tolerant Lewis acid catalyst for Michael addition of amines and indoles to α, β-unsaturated ketones under solvent-free conditions

The 1,4-conjugate addition of indoles and amines to cyclic and acyclic α, β-unsaturated ketones for C–N bond formation was efficiently carried out under solvent-free conditions at 50 °C using a catalytic amount of ZrOCl2·8H2O as a moisture tolerant Lewis acid. The reusability of the catalyst has been successfully examined without noticeable loss of its catalytic activity.

Graphical abstractZrOCl2·8H2O as a safe, inexpensive, air and moisture tolerant Lewis acid catalyst were used for efficient Michael addition of indoles and amines to cyclic and acyclic α, β-unsaturated ketones under solvent-free conditions at 50 °C without any side reactions. The catalyst successfully reused several times for next round of reactions. Figure optionsDownload full-size imageDownload high-quality image (34 K)Download as PowerPoint slide