Diastereoselective Synthesis of Double Axially Chiral Indole Derivatives via Friedel–Crafts Biarylation

We report a copper-catalyzed Friedel–Crafts biarylation protocol that delivers C3-site-selective doubly axially chiral biaryl indoles using five-membered cyclic diaryliodonium salts as biarylating agents. This atom-economical and highly diastereoselective protocol delivers a diverse library of biaryl indoles, accommodating a broad range of functional groups in good to excellent yields. Additionally, successful reaction scale-up execution and the efficient synthesis of 9H-dibenzo[a,c]carbazole further highlight the practicality of the developed protocol.