Deacylative Alkylation vs. Photoredox Catalysis in the Synthesis of 3,3'‐Bioxindoles

Abstract

The synthesis of 3,3'‐bioxindoles employing deacylative alkylations (DaA) in one‐pot process, where the 3‐bromooxindoles are generated in situ, is described. Good yields and moderate diastereoselections are obtained. By the modification of this procedure the synthesis of pure 3‐bromooxindoles through a deacylative bromination (DaB) is achieved. These bromides are efficiently employed in a photoredox dimerization process to get the desired 3,3'‐bioxindoles in good yields and low diastereoselections. In this single‐electron‐transfer (SET) mechanism the presence of a high quantum‐yield iridium(III) complex ensures high conversions in short reaction times.