Co(III)-Catalyzed C7 Alkynylation of Indolines with Bromoalkyne

In this work, Co-catalyzed C-7 alkynylation of indoline has been revealed with good to excellent yields. A range of alkynylated indolines were generated under mild conditions. Kinetic isotope studies indicated that the formation of cobaltacycle might be a turn-over limiting step. Additionally, gram-scale synthesis and oxidation of indoline to indole have been carried out successfully with excellent yields.