Fe(Ⅲ )-Catalyzed Heterocyclization Based On α-Substituted-β-dicarbonyl Compounds

With a sharp deterioration in the global ecological environment, human beings are facing an unprecedented crisis of survival, how to achieve sustainable development have become major problems. In recent years, in order to eliminate the pollution from the source, saving resources as the core of green chemistry research has become to solve the increasingly serious environmental problems of the powerful tool. Therefore, the development of efficient non-toxic, green, inexpensive catalyst system has become an important part of modern organic chemistry research. Compared with gold, rhodium, ruthenium, palladium and other precious metals, iron catalyst are inexpensive, environmentally friendly, so the iron-catalyzed reaction has become a hot research in organic chemistry. And the typies of reactions catalyzed by iron salts also continue to emerge, including oxidation, reduction , coupling, replacement, addition, cycloaddition and ring extensions, multicomponent reactions, and so on.This dissertation mainly discusses using iron（Ⅲ） salts as catalysts, several important application classes of heterocyclic compounds, including quinolinones, pyrroles, pyrazoles and enamintones are synthesized based on theα-substituted-β-dicarbonyl compounds by intramolecular cyclization or intermolecular tandem reaction. In the specific research process, we mainly have completed the following major tasks:（1） we determined the optimizing conditions through screening of reaction conditions like the catalyst, solvent, reaction temperature and so on, and synthesized several series heterocyclic compounds and enamintones under optimal conditions.（2） We studied the reaction mechanism in-depth by theoretical calculations and capturing reaction intermediates, so that we understood the reaction rules and the important role of iron（Ⅲ） salts as catalysts.This dissertation is divided into five chapters. The first chapter introduce reviews the development of research on iron catalysts in recent years. And the dissertation proposal was presented in the second chapter.The third chapter, we fistly realized the intramolecular aromatic C-H alkenylation of arenes with non-activated ketones to synthesize 4-alkenylquinolin-2-ones prosessing anti-HIV activities by using FeCl₃ as a catalyst and N-alkyl-α,α-dialkyl substituted acetoacetarylamides as starting materials. According to theoretical calculations and experimental plans, the possible reaction mechanism is proposed.The fourth chapter shows a novel strategy for the synthesis of polysubstituted pyrroles via[4C+1N] cyclization of 4-acetylenic ketones with primary amines by using the iron（III） salt as a catalyst. And the possible reaction mechanism is proposed.The fifth chapter briefly involves iron（Ⅲ） salts-catalyzed aminalysis ofβ-carbonyl 1,3-dithianes to synthesize stereodefined enaminones and 3,4-disubstituted pyrazoles.