Copper-Catalyzed Cross-Couplings Under Improved Conditions And Their Applications For The Assembly Of Heterocyclic Compounds Via One-Pot Reactions

One of the task of organic synthesis is the efficient C(sp2)-X (X= N, O, S, etc) or C(sp2)-C bond formation. Transition metal-catalyzed coupling is an important protocol for C(sp2)-X or C(sp2)-C bond formation. Exploring the green, economic, efficient and versatile catalytic systems is of great significance for their practical applications, because they meet the demand for industrialization and environmental protection.Copper-mediated C-X bond formation has drawn considerable attention for their lower cost and lower toxicity. In recent years, great progress has been achieved in copper-catalyzed coupling under improved conditions.Based on our research in the copper(Ⅰ)-catalyzed coupling and green chemistry, this dissertation firstly studied the copper-catalyzed coupling reactions under improved conditions (chapters 2-3). We found that a room temperature ionic liquid ([Bmim]BF4) was a favorable solvent for the copper(Ⅰ)-catalyzed coupling of aryl/heteroaryl bromides with imidazoles, making the catalytic system green and recyclable. We also found that aβ-keto ester (ethyl 2-oxocyclohexanecarboxylate) was a novel, efficient and versatile ligand for copper(Ⅰ)-catalyzed C-N/C-O/C-S coupling reactions under mild conditions.Recently, copper-catalyzed coupling reactions have been successfully applied to the efficient assembly of various heterocyclic compounds via one-pot strategies. Our group is also interested in the related research. This dissertation next studied the application of copper(Ⅰ)-catalyzed coupling into the synthesis of heterocycles through one-pot methods (chapters 4-5). And we found that some potentially useful heteroaromatics such as 2-iminobenzo-1,3-oxathioles and 2-heterobenzimidazoles could be facilely and efficiently synthesized from readily available materials via copper(I)-catalyzed one-pot intermolecular addition/intramolecular coupling protocols.