Intramolecular Addition of a Dimethylamino C(sp3)–H Bond across C–C Triple Bonds using IrCl(DTBM-SEGPHOS)(ethylene) Catalyst: Synthesis of Indoles from 2-Alkynyl-N-methylanilines

Intramolecular addition of a C(sp3)–H bond of the dimethylamino group across the C–C triple bond in 2-alkynyl-N,N-dimethylanilines is effectively catalyzed by a new iridium complex, IrCl(DTBM-SEGPHOS)(C2H4), in mesitylene at 150 °C. The intramolecular C(sp3)–H addition is followed by double-bond isomerization to afford 3-substituted indoles in good to high yields.