Redox-Neutral Generation of Iminyl Radicals by <i>N</i>-Heterocyclic Carbene Catalysis: Rapid Access to Phenanthridines from Vinyl Azides

Abstract

-heterocyclic carbene-catalyzed oxidant-, metal- and light-free iminyl radical generation pathway stemming from the reaction of vinyl azide and α-bromo ester is uncovered. This newly developed methodology is successfully applied to the redox-neutral construction of a number of diversified phenanthridine derivatives with nice functional group compatibility. Insights from the mechanism study reveal that this NHC-catalyzed transformation potentially proceeds through an alkyl radical addition-initiated HAS process, with the iminyl radical as an active intermediate.

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