Photodriven Photocatalyst/Metal-Free Direct C-C/C-N Bond Formation: Synthesis of Indoles via EDA Complexes.

The photodriven direct C-C/C-N bond formation initiated by electron donor-acceptor (EDA) complexes for the synthesis of indoles has been accomplished via [3+2] annulations of secondary arylamines with alkynes using IC4F9 as oxidants in the absence of any photocatalysts and metals. This green transformation exhibits the advantages of operational simplicity, good functional tolerances, and mild reaction conditions. The in situ generated EDA complexes derived from arylamines with alkynes were characterized by UV-vis absorption spectrometry and NMR titration experiments.