The biaryl unit containing a heteroatom is a key structure in a large number of natural products and π-conjugated organic systems. The cross-couplings can provide powerful methods for the construction of biaryls and heterobiaryls; thus the development of a new coupling method has been intensively studied by synthetic chemists. Therefore, the oxidative biaryl coupling reaction of arenes containing a heteroatom is a significantly attractive, convenient, and straightforward route to the synthesis of biaryls due to its operational simplicity avoiding the preparation of the corresponding halogenated and metallated arenes. In this report, recent progress in the field of metal-free oxidative cross-coupling reactions of aromatic compounds using hypervalent iodine(III) reagents, is presented.1 Introduction2 Cyanation and Halogenation Reactions of Heteroaromatic Compounds3 Biaryl Coupling Reaction of Heteroaromatic Compounds3.1 Regioselective Coupling Reaction of Thiophenes3.2 Cross-Coupling Reaction of Thiophenes3.3 Coupling Reaction of EDOT and Pyrroles3.4 Cross-Coupling Reaction of Pyrroles4 Cross-Coupling Reaction of Anilines5 Cross-Coupling Reaction of Phenols6 Cross-Coupling Reaction of N-Heteroaromatics with Aryl Radicals from Diaryliodonium(III) Salts7 Conclusion
Clean and Direct Synthesis of α,α′-Bithiophenes and Bipyrroles by Metal-Free Oxidative Coupling Using Recyclable Hypervalent Iodine(III) Reagents
