Shaking Up the Friedländer Reaction: Rapid, Scalable Mechanochemical Synthesis of Polyaryl‐Substituted Quinolines

Abstract Quinolines are ubiquitous heterocyclic aromatic scaffolds, which can be found in many natural and synthetic products. They are highly valued for their pharmacological and electrochemical properties, encouraging the discovery of new routes for quinoline synthesis and diversification. In particular, polyaryl‐substituted quinolines have recently surged as useful substrates for a wide variety of applications, yet their synthetic routes remain difficult and inefficient. Herein, we report a rapid and novel mechanochemical Friedländer synthesis of polyaryl‐substituted quinolines under basic conditions using ball milling. The optimized reaction conditions resulted in moderate to excellent yields ranging from 48% to >95% and demonstrated broad functional group tolerance at 1 hour reaction times. We further show a new route for the synthesis of photocatalyst DPQN 2,4−di−OMe and photo‐ligand PPQN 2,4−di−OMe as well as OLED donor‐acceptor pCzPPQ, electron transport material oligoquinoline TQB and organic semiconductor DPA. A gram scale reaction was also achieved using Resonant Acoustic Mixing (RAM), providing an isolated yield of 87% after a simple recrystallization in ethanol.