Through‐Space 1,4‐Palladium Migration and 1,2‐Aryl Shift: Direct Access to Dibenzo[a,c]carbazoles through a Triple CH Functionalization Cascade

A palladium‐catalyzed expeditious synthesis of dibenzofused carbazoles from readily available 2‐arylindoles and diaryliodonium salts is reported. Interestingly, after the electrophilic C3 palladation of indole, an unexpected “through‐space” 1,4‐palladium migration to the 2‐aryl moiety, by remote C?H bond activation followed by C?H arylation with diaryliodonium salt, and an unprecedented 1,2‐aryl shift take place. Finally, an intramolecular cross‐dehydrogenative coupling (CDC) at the C2 position affords dibenzoa,c]carbazoles in high yields. Remarkably, the present migratory annulation occurs through three C?H bond activation one C?C bond cleavage, and the simultaneous construction of three new C?C bonds in a single operation.