Visible-Light-Mediated Decarboxylative Alkylation Cascade Cyano Insertion/Cyclization of N-Arylacrylamides under Transition-Metal-Free Conditions.

The visible-light-mediated decarboxylative functionalization of aliphatic carboxylic acids using organocatalysts has rarely been reported. This study represented an environmentally benign decarboxylation method involving the combination of eosin Y and (NH4)2S2O8. This system converted aliphatic carboxylic acids to alkyl radicals, followed by their addition to the carbon-carbon double bond of the N-arylacrylamide cascade cyano insertion/cyclization to construct alkylated phenanthridines in moderate to good yields under photoredox catalysis.