The arylethylamine
pharmacophore is conserved across a range of
biologically active natural products and pharmaceuticals, particularly
in molecules that act on the central nervous system. Herein, we present
a photoinduced copper-catalyzed azidoarylation of alkenes at a late
stage with arylthianthrenium salts, allowing access to highly functionalized
acyclic (hetero)arylethylamine scaffolds that are otherwise difficult
to access. A mechanistic study is consistent with arac-BINAP-CuI-azide (2) as the photoactive catalytic
species. We show the utility of the new method by the expedient synthesis
of racemic melphalan in four steps through C–H functionalization.