Pallaidum-catalyzed Buchald-Hartwig Amination And Suzuki Coupling Of Aromatic ES

Heterocyclic-aromatic cyclic amines,heterocyclic-heterocyclic arylamines,and diaryl?hetero?ketone structures are widely found in pharmaceuticals,biologically active compounds,and functional materials.These structures could be constructed by the Buchwald-Hartwig amination reaction and Suzuki-Myauri cross-coupling reaction.Considering that the existing of low activities of deactivated substrates as well as the harsh reaction conditions,herein,in this thesis,we focused on the developing a series of functional N-heterocyclic carbene palladium complexes to overcome the above shortcomings in Pd-catalyzed transformations.1.According to the“Bulky-yet-Flexible”design concept,a series of carbene palladium complexes?C1-C3?with long alkyl chain on N-moieties were syntheisized and characterized by ¹H NMR and ¹³C NMR.To analyze the steric hindrance effect of the ligand,the single crystal structures of C1 and C2 were further determined by X-ray diffraction.In the process of the amination,the planar ancenaphthyl skeleton structure enhanced the electron donating ability and increased the rate of oxidation addition.The introduction of a flexible long alkyl chain on the N-moieties increases the steric hindrance,which would protect the active palladium center and promote the reduction elimination reaction.Meanwhile,the characteristics of the flexiblility of the long alkyl chain would not inhibit the oxidative addition reaction.This design concept was verified by examining the catalytic effect on the amination reaction of heterocyclic halogenated aromatic hydrocarbons with heterocyclic amines when n-heptane was used as the reaction solvent.2.With the glyoxal framework,a hindered N-moities on nitrogen heterocyclic carbene palladium complex of M1 was designed and characterized by ¹H NMR and ¹³C NMR.Since the reaction mechanism of this type of aryl ketone is related to the Suzuki coupling reaction.Therefore,the oxidative addition reaction is considered as the rate-limiting step of the catalytic cycle,and a large sterically hindered group pyrene group is introduced on the para position of the N-aromatic ring.The large?-?conjugated pyrene group enhances the electron donating ability of the?electron to facilitate oxidation plus into a reaction.At the same time,the fluorenyl group is located far away from the palladium center,which can stabilize the palladium center without adversely affecting the oxidation addition step.The heterocyclic aryl ester and heterocyclic boronic acid were selected as the reaction substrates,and the catalytic efficiency of the coupling reaction was confirmed by the palladium complex to verify the design concept of our precatalyst.3.The excellent catalytic performances of the precatalysts on these deactivated substrates demonstrated the correctness of our catalyst design concept,which would provide a new viewpoint of the design of nitrogen heterocyclic carbene palladium complexes in Pd-catalyzed cross-coupling reactions..