Visible-light-promoted radical cascade alkylation/cyclization: access to alkylated indolo/benzoimidazo[2,1- a ]isoquinolin-6(5 H )-ones.

A new protocol is herein described for the direct generation of alkylated indolo/benzoimidazo[2,1- a ]isoquinolin-6(5 H )-one derivatives by using Hantzsch esters as alkylation radical precursors using a photoredox/K 2 S 2 O 8 system. This oxidative alkylation of active alkenes involves a radical cascade cyclization process and a sequence of Hantzsch ester single electron oxidation, C-C bond cleavage, alkylation, arylation and oxidative deprotonation.