Development of Metal-Free, Trifluoromethanesulfonic Acid-Immobilized Nitrogen-Doped Carbon Catalysts for Povarov Reactions.

A metal-free, heterogeneous acid catalyst, trifluoromethanesulfonic acid-immobilized nitrogen-doped carbon catalyst, was developed for Povarov reactions. This catalyst exhibited excellent catalytic activity, achieving high turnover frequency (>400 h) and good cis-selectivity of the desired 1,2,3,4-tetrahydroquinoline products. The reaction had a broad substrate scope, and the multicomponent Povarov reaction proceeded smoothly with readily accessible aldehydes and anilines. The heterogeneity and reusability of this catalytic system were confirmed. The catalyst was characterized by spectroscopic and microscopic analysis studies.