Additions of Aldehyde-Derived Radicals and Nucleophilic -Alkylindoles to Styrenes by Photoredox Catalysis.

The consecutive addition of acyl radicals and -alkylindole nucleophiles to styrenes was established, as well as some additional radical-nucleophile combinations. Both aryl and aliphatic aldehydes give reasonable yields. The reaction proceeds best for α-substituted styrenes, effectively creating a quaternary all-carbon center. Some iridium-based photoredox systems are catalytically active; furthermore, a base is needed in this transformation. Radicals are formed by reductive perester cleavage and hydrogen atom transfer.