Synthesis Of A Variety Of Aromatic Heterocyclic Compounds Via An Oxidative Dearomatization Strategy

90%of chemicals discovered in nature contain cyclic unit, and many of them are heterocyclic compounds containing a hetero atom, such as N-heterocycles. Thus, the development of efficient methods for the construction of N-heterocycles has attracted continuous interest in organic synthesis. The oxidative dearomatization strategy, which meets the requirement of green synthesis, is widely used in the synthesis of heterocyclic compounds. In recent years, numerous studies focused on on the oxidative dearomatization of phenols, however, little attention was put into the oxidative dearomatization of aromatic amines. For this reason, our group did some research in the field, and obtained certain achievements. In this thesis, the main work is devoted to the synthesis of a variety of N-heterocycles via the oxidative dearomatization strategy.Firstly, a new strategy for accessing N-heteroarylated indoles and benzimidazoles, which were prepared through metal-catalyzed tandem reactions between2-alkynyl cyclohexadienimines or cyclohexadienones and2-alkynylanilines or N1-benzylbenzene-1,2-diamine, has been developed. The potential of this method is shown by its adaptability to a wide variety of reagents, mild reaction conditions and simple manipulation.Secondly, a dearomatization strategy of β-enamino esters was developed to construct indenoazepine derivatives. The oxidative dearomatization was combined with a base-promoted tandem Michael addition/polycyclization and an acid-catalyzed aromatization. After exploring the mechanism, we found that the nonaromatic structure of the Michael adducts might be essential to the realization of the7-endo-dig cyclization.Finally, An alternative approach to prepare phenothiazines through PhI(OAc)2mediated oxidative dearomatization of phenols or anilines and CuI-catalyzed domino reaction with2-aminobenzenethiols is developed. The raw materials are simple and easy to get, the procedure was operated in a mild, green and economic way.