Tandem iridium-catalyzed decarbonylative c-h activation of indole: Sacrificial electron-rich ketone-assisted bis-arylsulfenylation

Abstract

Described herein is a decarbonylative tandem C-H bis-arylsulfenylation of indole at the C2 and C4 C-H bonds through the use of pentamethylcyclopentadienyl iridium dichloride dimer ([Cp∗IrCl2]2) catalyst and disulfides. A new sacrificial electron-rich adamantoyl-directing group facilitates indole C-H bis-functionalization with a traceless in situ removal. Various differently substituted disulfides can be easily accommodated in this reaction by a coordination to Ir(III) through the formation of six- and five-membered iridacycles at the C2 and C4 positions, respectively. Mechanistic studies show that a C-H activation-induced C-C activation is involved in the catalytic cycle.