MCM-41-supported Phosphine Gold(?)Complexes-Catalyzed Construction Of N-heterocyclic Compounds

In this dissertation,we describe applications of the MCM-41-supported phosphine ?complexes in construction of N-heterocyclic compounds,which mainly includes the following four parts:1.The mesoporous MCM-41 was condensed with triethoxysilyl-functionalized triphenylphosphine ligand in anhydrous toluene to generate MCM-41-supported phosphine ligand?MCM-41-PPh₃?.The latter was reacted with Me₂SAuCl in dry DCM to give an MCM-41-supported phosphine ?complex catalyst?MCM-41-PPh₃-AuCl?.The structure of the catalyst was characterized by various techniques.The MCM-41-PPh₃-AuCl was then used to catalyze the cyclization of amidine hydro-chlorides with propiolaldehydes.It was found that this hetrogeneous ?complex exhibited good catalytic activity under mild reaction conditions,yielding a variety of disubstituted pyrimidine compounds in good to excellent yields,and can be recycled up to seven times without significant loss of activity.2.MCM-41-supported phosphine ?complex?MCM-41-PPh₃-AuCl?was reacted with AgNTf₂ in DCM at room temperature for 0.5 h to afford the MCM-41-PPh₃-AuNTf₂ complex and the ?complex was characterized by various tech-niques.Then,we investigated heterogeneous ?-catalyzed cascade annulation of various aldehydes with propargylamine by using MCM-41-PPh₃-AuNTf₂ as catalyst leading to a variety of 3-substituted 2,5-dimethylpyrazines in good to excellent yields.This supported ?catalyst can be recycled up to seven times and its catalytic efficiency remains unchanged.3.We investigated heterogeneous ?-catalyzed[2+2+2]annulation between ynamides and nitriles by using MCM-41-PPh₃-AuNTf₂ as catalyst.It was found that in the presence of catalytic amount of MCM-41-PPh₃-AuNTf₂,the annulation reaction of a wide range of ynamides with various nitriles proceeded smoothly to produce a variety of tetrasubstituted pyrimidines.The present protocol has advantages of readily available starting materials,mild reaction conditions,high yields,and the catalyst recyclability,providing a convenient and practical route for the synthesis of a variety of tetrasubstituted pyrimidine derivatives.4.The mesoporous MCM-41 was condensed with triethoxysilyl-functionalized diphenylphosphine ligand in anhydrous toluene to generate MCM-41-supported phosphine ligand?MCM-41-PPh₂?.The latter was reacted with Me₂SAuCl in dry DCM,followed by the treatment with AgNTf₂ to give an MCM-41-supported phosphine ?complex?MCM-41-PPh₂-AuNTf₂?.We applied this heterogeneous ?catalyst to the oxidative ring expansion of 2-alkynyl-1,2-dihydropyridines or quinolines to azacyclic seven-membered ring compounds.The results showed that this heterogeneous ?-catalyzed oxidative ring expansion reaction has advantages of wide scope of substrates,mild reaction conditions,and high yileds and the catalyst can be recycled up to seven times without significant loss of activity.