Base-Promoted, Aerobic, and Regioselective Carbon–Hydrogen Bond Activation of Thiophene with Group 9 Metalloporphyrins

Base-promoted aerobic carbon–hydrogen bond activation (CHA) of thiophene was achieved with high regioselectivity at the 2-position by group 9 metalloporphyrins in moderate to high yields. Mechanistic investigations suggest a homolytic aromatic substitution through MII(ttp) (M = Rh, Ir) metalloradical addition, followed by β-elimination of a metal hydride pathway.