Magic Blue-Initiated S_N2‑Type Ring Opening of Activated Aziridines: Friedel–Crafts-Type Alkylation of Electron-Rich Arenes/Heteroarenes

A transition metal-free, atom-economical, and highly stereospecific synthetic approach to Friedel–Crafts-type alkylation of arenes/heteroarenes has been developed. The protocol involves the catalytic aminium radical-cation salt (Magic Blue)-initiated S_N2-type nucleophilic ring opening of activated aziridines with arenes/heteroarenes to give the corresponding 2,2-diarylethylamines up to 99% yield and 85% ee (for nonracemic aziridines) in a very short reaction time. Moreover, on reaction with 1,3-dimethylindole and benzofuran, aziridines undergo domino-ring-opening cyclization (DROC) to give the various biologically significant heterocyclic scaffolds in moderate to good yields.