DDQ Promoted Cross-Dehydrogenative-Coupling Reactions And D-Glucosamine As A Ligand In The Application Of N-Arylation Of Imidazole

Based on our research in the copper(â… ) catalysis and green chemistry,this dissertation has firstly studied the copper(â… )-catalyzed reaction.We have disclosed that D-glucosamine,a natural ligand,can accelerate the N-arylation of imidazoles with aryl and heteroaryl halides using CuI as a catalyst.Compared with the catalytic effect of naturaI amino acids,D-glucosamine shows similar catalytic activity.Thus it provides a green ligand for selection of copper-catalyzed N-arylation for practical use.With the emergence of the concepts of "atom economy" and "green chemistry", the cross-coupling for C-C bond formation via transition metal-catalyzed C-H activation is a challenging subject.In the cross-dehydrogenative-coupling(CDC) reaction,the copper(â… ) was frequently used as a catalyst.With the development of the copper(â… ) in the catalytic reaction,we have studied the CDC reaction between 1. 3-diarylallylic and active methylenic compounds and hoped that the copper(â… ) can catalyze the coupling reaction.However,according to the reaction results,it only requires DDQ as the oxidative reagent and the copper(â… ) seems no obvious catalyti(?) effect.No metal catalyst is in fact a better selection in the view of green chemistry.S(?) in the following research,we have studied the CDC reaction via oxidative C-H activation without metal catalyst.On the basis of above finding,we have next explored the coupling between(?) 3-diarylpropynes and active methylenic compounds.Compared with the(?) 3-diarylpropenes,1,3-diarylpropynes show slightly lower reaction activities.As far as the electronic effect of the benzylic ring was concerned,it has been found that electron-donating substituents can accelerate the desired C-C bond-forming process. Various active methylenic compounds are subjected to this cross coupling reaction.We have finally explored the CDC reaction between 1,3-diarylpropenes and amides,sulfonamides.The reaction gives the good yields under the heating condition. It is applicable to the coupling of 1,3-diarylpropene with aryl,heteroaryl,and alkyl amides and sulfonamides.The above three parts that mainly involved the formation of C-C bond and C-N bond,which are difficult to construct by the traditional method,could be directly realized with high efficiency via CDC reaction.In the view of the simplicity of the operation,short procedure,availability of the material and atom economical,the above procedures are very ideal methods and provide the concise and efficient methods for the synthesis of the corresponding compounds.