Photoredox-catalyzed synthesis of a novel class of fluoroalkyl pyrazolones

Abstract

A photoredox-enabled strategy is developed for the regioselective synthesis of fluoroalkyl 2-pyrazolin-5-ones via radical addition–cyclization cascades. This metal-free approach enables the efficient incorporation ofperfluoroalkyl and difluoromethylene groups into methacryloyl hydrazide under mild conditions. The protocoldemonstrates broad substrate scope, functions in both batch and continuous flow systems, and proceeds through aphoto-oxidative quenching mechanism. This method provides a sustainable and versatile route to fluorinated het-erocycles with promising applications in medicinal chemistry.