Nitrogen-rich isoindoline-based porous polymer: Promoting knoevenagel reaction at room temperature

Abstract

Nitrogen-rich porous organic polymers (POPs) with basic features have already shown promising performance in various organic reactions. But the harsh conditions, tedious synthetic methods and the requirement of specific monomers impede their further application. Herein, we introduce isoindoline chemistry into POP community. An isoindoline formation process between aniline and bromomethylbenzene—coupling nucleophilic substitution, HBr elimination, and intramolecular cyclization in one pot, is utilized for POPs synthesis. Nitrogen-rich isoindoline-based porous polymers (IPPs) were obtained with specific surface areas up to 408 m2 g−1. Unexpectedly, mechanochemistry could enable the rapid (3 h) and solid-state synthesis of IPP catalysts. Moreover, this nitrogen-rich catalyst presents excellent activity (isolated yield: 99%), scalable ability (up to 14 g per run) and recyclability (five runs) towards the Knoevenagel condensation reaction under mild reaction conditions (water as solvent at room temperature).