Metal-Free Oxidative C–C Coupling of Arylamines Using a Quinone-Based Organic Oxidant

A variety
of arylamines are shown to undergo oxidative C–C
bond formation using quinone-based chloranil/H+ reagent
as the recyclable organic (metal-free) oxidant system to afford benzidines/naphthidines.
Arylamines (3°/2°) designed with various substituents were
employed to understand the steric as well as electronic preferences
of oxidative dimerization, and a mechanism involving amine radical
cation has been proposed. The tetraphenylbenzidine derivative obtained
via oxidative C–C coupling has been further converted to blue-emissive
hole-transporting material via a simple chemical transformation. This
study highlights the preparation of novel HTMs in a simple, economic,
and efficient manner.