Synthesis of π-Functional Molecules through Oxidation of Aromatic Amines.

In this review, we focus on the synthesis of π-conjugated functional molecules by the oxidation of aromatic amines, which is one of the most effective methods for the construction of C-C, C-N, and N-N bonds between two π-conjugated molecular units, and consider their characteristics and applications. Polyanilines are the most common products of the oxidation of aromatic amines; however, azobenzenes, phenazines, and 1,1'-binaphthyl-2,2'-diamines may be produced in this manner also, depending on the reaction conditions. Recent advances in the methodology of aniline oxidation have led to the development of high-regioselectivity industrial-scale syntheses of optically or electroactive π-functional dyes containing nitrogen atoms. In particular, the regioselective fusion of π-extended aromatic amines can be used to prepare distorted π-conjugated molecules under mild reaction conditions, allowing the construction of unprecedented curved nitrogen-containing π-conjugated molecules.