Photochemical Decarboxylative Radical Alkylation/Cyclization Reaction to Fused Nitrogen Heterocycles by <scp>LiI</scp>/<scp>PPh₃</scp> Catalysis

Abstract

Comprehensive Summary A visible‐light‐induced decarboxylative radical cascade cyclization reaction between N ‐(2‐cyanoaryl)‐acrylamides and alkyl N ‐(acyloxy)phthalimide (NHPI esters) for the construction of phenanthridine derivatives has been developed. This approach utilizes lithium iodide (LiI) and triphenylphosphine (PPh 3 ) as the redox catalysts and the alkyl radical is produced through the photoactivation of the electron donor‐acceptor (EDA) complex. A series of primary, secondary, and tertiary alkyl‐substituted phenanthridines are prepared in up to 82% yield without transition‐metal catalysts, chemical oxidants, or metal‐/organic dye‐based photocatalysts.

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