Photoinduced Copper-Catalyzed Late-Stage Azidoarylation of Alkenes via Arylthianthrenium Salts

The arylethylaminepharmacophore is conserved across a range ofbiologically active natural products and pharmaceuticals, particularlyin molecules that act on the central nervous system. Herein, we presenta photoinduced copper-catalyzed azidoarylation of alkenes at a latestage with arylthianthrenium salts, allowing access to highly functionalizedacyclic (hetero)arylethylamine scaffolds that are otherwise difficultto access. A mechanistic study is consistent with a rac-BINAP-Cu-I-azide (2) as the photoactive catalyticspecies. We show the utility of the new method by the expedient synthesisof racemic melphalan in four steps through C-H functionalization.