Photoredox-Catalyzed Arylative and Aryl Sulfonylative Radical Cascades Involving Diaryliodonium Reagents: Synthesis of Functionalized Pyrazolones

Abstract

We disclose a photoredox-catalyzed arylative radical cascade between N'-arylidene-N-acryloylhydrazides and diaryliodonium reagents to provide corresponding benzylated pyrazolones in good yields. The protocol was extended to three-component coupling involving 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO) as a sulfur dioxide surrogate for the synthesis of arylsulfonylated pyrazolones. Both reactions exhibit broad scope, scalability, and high functional group tolerance.