Indium Catalyzed Sequential Regioselective Remote C−H Indolylation and Rearrangement Reaction of Peroxyoxindole

Abstract Indium‐catalyzed sequential remote C−H functionalization (C‐6 position) and C3‐indolylation of peroxyoxindole using indole is described for the synthesis of terindolinone derivatives. Whereas, N‐substituted 3‐phenyl peroxyoxindole derivatives undergoes consecutive skeletal rearrangement to generate transient carbocation, which has been trapped with indole nucleophile to generate 2‐(1H‐indol‐3‐yl)‐4‐alkyl‐benzo[b][1,4]oxazin‐3(4H)‐one derivatives. In contrast with Indium (III) Chloride, FeCl3 ⋅ 6H2O facilitates oxidative cleavage of the peroxyoxindole (Hock cleavage) and further reaction with indole to afford biologically important trisindoline derivatives. A plausible mechanism has been proposed for these reactions with experimental evidences. magnified image