Iodine-photoredox dual catalysis unlocks bifunctional reactivity of α-diazoesters in radical cascade cyclization reactions via remote C–I bond dissociation

Abstract

Current radical cascade cyclization reactions involving α-diazoesters mainly rely on a photo-driven proton-coupled electron transfer (PCET) path. In contrast, iodine-photoredox dual catalyzed radical cascade cyclization of α-diazoesters remains unexplored. In this work, we report the first divergent cycloaddition strategy that employs diazo compounds as C1 building blocks for the construction of fused five-membered rings under iodine-photoredox dual catalysis. Differing from the prior PCET strategy, this approach unlocks the bifunctional reactivity of α-diazoesters, enabling them to serve both as radical precursors and radical trappers in radical cascade cyclization processes, providing a new mode of radical cascade cyclization of α-diazoesters catalyzed by visible light.