Preparation Of Highly Efficient And Regional Selective N,/Se-Bidentate Ligands

In past decades,the synthesis of bidentate ligands as high catalytic efficient additives or as Prep.have been extensively investigated in organic synthesis,such as BINAP,DPEphos,2,2'-bipyridine,and N,O/P-bidentate ligand,etc.However,the synthesis of N,S/Se-bidentate ligand is rarely investigated because even very low concentrations of disulfide or thiol species can rapidly and irreversiblydeactivate the catalyst.Recently,the traditional synthesis of N,S-bidentate ligand is required the muti-steps preparation(such as NBS bromination and base abstraction,etc),leading to a large amount of HX or salt waste and hard to fulfil the requirement of green chemistry.We described an highly efficient and regioselective C-S cross coupling method for the synthesis of N,S-bidentate ligands with good to excellent yields.And its application in synthesis of N,Se-bidentate ligands is also successfully achieved.To our knowledge,it is the first report of synthesis of N,Se-bidentate ligands via C-H functionalization.In this thesis,we successfully found an ideal reaction condition,with 2 equivalents of CuBr2 as oxidative reagent,and 10 mol%of Pd(OAc)2 as catalyst,the 2-phenylpyridine can reacted with PhSSPh for 24 hours at 140? in DMF in a sealed tube with high yield(isolated yield is 84%),We also found 2-phenylpyridines with the methyl group attached in the pyridine cycle with high reactivity,in current ideal conditions,and the(p-BrC6H4S)2 and 1,2-bis(2,5-dichlorophenyl)disulfane also get high yield respectively.Then we move to the carbazole derivatives with pyridmine as directing group,which also shows high catalytic efficiency in C-S cross-coupling reactions via ortho-C-H functionalization and S-S bond cleavage with several diaryl(dialkyl)disulfides.We also found our system can be applied in benzo[h]quinoline with moderate to excellent yields.The indole derivatives with pyrimine as directing group are also adopted to screen the application scope of the current catalytic system.With C-S cross coupling method is successfully developed viaortho-C-H functionalization of 2-phenyl-pyridine,carbazole,benzo[h]quinoline and indoles derivatives with disulfides,we expand its application in C-Se bond formation with current substrates with diphenyl diselenide.After simple optimization of the reaction time and temperature to 80?for 48 hours,the yield of carboazole derivatives shows quantitative yields and the benzo[h]quinoline and indole derivatives are also show high reactivityThen we proposed a plausible mechanism for the present reaction.The N,S/Se-bidentate ligands have been characterized by XRD,NMR.