Visible‐Light Photoredox Catalysis in the Intramolecular Dicarbonylation of Alkenes: Catalyst‐Dependent Divergent Syntheses of Both 1,4‐Dicarbonyls and α‐Hydroxy‐β,γ‐Unsaturated Lactams From 1,2‐Dicarbonyls

In this study, catalyst‐dependent divergent syntheses were developed to produce both 1,4‐dicarbonyls and α‐hydroxy‐β,γ‐unsaturated lactams from 1,2‐dicarbonyls under visible light photoredox catalysis. Intramolecular dicarbonylation of vinyl halides under metal‐free either thermal or visible‐light photocatalytic conditions was explored to produce a series of 1,4‐dicarbonyls with two different carbonyl moieties and a lactam ring. The same substrates were also converted to α‐hydroxy‐β,γ‐unsaturated lactams with an α‐quaternary center under iridium‐based visible‐light photoredox catalysis. These unique results are the first report on photocatalytic intramolecular dicarbonylation of alkenes to accomplish the synthesis of 1,4‐dicarbonyls from 1,2‐dicarbonyls via a two‐carbon insertion.