Transition-metal Catalyzed Cascade Reaction And Construction Of N-containing Heterocycles

Recently, transition metal-catalyst coupling reactions and C-H bond activation reactions have become the most useful methods for C-C bond and C-X(X=C, O, N, etc.) bond formation. At the same time, one pot synthesis of heterocyclic compounds via cascade process containing these kinds of reactions is the focus of methodology studies in organic chemistry. Cascade reactions own advantages in shortening the reaction steps and reducing waste discharge, it is environment friendly and economicly. As the abundant, cheap, and less toxic elements, synthesizing heterocyclic compounds via iron and copper catalized cascade reactions should be more practical.The dissertation mainly contains five fields as follows:The first chapter is a review of recent progresses in transition metal Fe, Cu, Pd catalyzed cascade reactions for the construction of heterocyclic compounds.Secondly, we have developed an efficient Fe(acac)3-catalyzed tandem oxidative addition/cyclization reaction of simple amides with N-arylacrylamides in mild condition. Two C-C bond were formed and a series of 3-amido oxindoles were constructed, providing a strategy to screen for the bioactive molecules.Thirdly, we have realized copper promoted radical addition/cyclization of azobisisobutyronitrile with arylacrylamides, which provide a convenient process to synthesize 3-(2’-cyano alkyl) oxindoles. In the reaction AIBN forms the 2-cyanoprop-2-yl radical for addition and hydrogen abstraction. There is no need to add oxidants. What’s more, the 3-(2’-cyano alkyl) oxindoles have the potential for converting into a diverse class of functionalities.Fourthly, midazobenzothiazine and primidobenzothiazine derivatives which have been reported to be important structural motif of many bioactive molecules were synthesized via an aliphatic SN2 substitution/Cu(Ⅰ) catalyzed Ullmann coupling cascade process.Fifthly, we studied the possibility of synthesizing benzimidazo[2,1-b] benzothiazoles via Cu(Ⅰ) catalyzed Ullmann coupling and Pd-catalyzed sp2 C-H functionalization casade reaction from iodobenzene and 2-benzothiazolethiol. Finaly, we synthesized benzimidazo[2,1-b]benzothiazoles through two steps.Sixthly, K2S2O8 promoted reaction of N-arylacrylamides with isopropyl diazenedicarboxylate was reported. The expected addition/cyclization reaction of N-arylacrylamides with carboxylic ester free radical, generated by diazenedicarboxylate, did not accour. Actually, we got the C-N amiation product. However, the products could be converted to heterocycles in further experiment.