Palladium‐Catalyzed Selective Aryl Ring C–H Activation of N ‐Acyl‐2‐aminobiaryls: Efficient Access to Multiaryl‐Substituted Naphthalenes

Palladium‐catalyzed cycloaromatization of N ‐acyl‐2‐aminobiaryls, through a sequence of ortho C−H bond activation/alkyne insertion/ meta C−H bond activation/alkyne insertion, was developed. An efficient synthesis of multiaryl‐substituted naphthalenes, N ‐[2‐(5,6,7,8‐tetraarylnaphthalen‐1‐yl)aryl]acetamides, was demonstrated using molecular oxygen as the sole oxidant. Furthermore, through Buchwald's synthetic protocol, two compounds were converted into corresponding fluorescent carbazoles in 30–40% yield by intramolecular C−N bond formation.