Silica-Supported LiHSO4 as a Highly Efficient, Mild, Heterogeneous, and Reusable Catalytic System for the Solvent-Free Synthesis of Bis(indolyl)methanes

Abstract

Silica-supported LiHSO4 (LiHSO4/SiO2) is used as a green, cheap, and efficient catalytic system for the synthesis of bis(indolyl)methanes via the condensation of indoles with carbonyl compounds under solvent-free conditions. The reactions proceed rapidly at room temperature, and the title compounds are obtained in high to excellent yields.