Design And Synthesis Of New Fluorenone Derivatives Based On C-H Activation Reaction

C-H activation reaction is gaining enormous attention in recent years due to its advantages in improved efficiency in the construction of C-C bond.Comparing to typical cross coupling reactions,C-H activation reaction is a more economical and efficient method for C-C bond formation,eliminating the extra steps for the installation of functional groups,such as boron esters,alkylenes,alkynyls,and even organometallic aryls.While constructing C-C bond through C-H activation reaction has the defect of poor regioselectivity,it is a great challenge to improve its regioselectivity.As of now,common methods have been used to solve this problem,which include the use of?-substituted substrates to eliminate the possible multiple activation sites,as well as introducing directing groups into the substrates.However,either of the method limited the diversity of possible substrates.Therefore,developing a simple and efficient C-H activation method that can control the regioselectivity in a broad range of substrates is of great need and interest.This thesis focuses on the study of C-H activation in polymer and small molecule synthesis.The following two parts of work have been carried out.1.Choosing fluorenone as the monomer,Pd-catalyzed direct arylation polymerization(DARP)was studied for the synthesis of fluorenone-based polymers.Through screening the reaction conditions,including the catalyst,ligant,acid,base,solvent and temperature,etc.,a highly efficient and regioselective DARP method was achieved.Two series of compounds,including conjugated oligomers and conjugated polymers of fluorenone with different heteroaromatics,were obtained in excellent yields following the one-step polymerization.Because of the donor-acceptor structure of fluorenone-based compounds,both oligomers and polymers demonstrated excellent optical properties,which included large Stokes shifts,wide emission coverage,and different energy band gaps.The water-soluble conjugated polymer PFOP-NEt3(+)was demonstrated to be a potential lysosomal fluorescence imaging probe,which could penetrate cell membrane and stain lysosome.2.To improve the regioselectivity of C-H activation,the functional group on the structures of two intermediates was used as directing groups to lead the C-H activation reaction.During the study of the reaction of cyanogen and diaryliodonium salt,the intermediates phenylnitrilium and amide was found,in which both contributed in forming the C-C bond.Via this method,the step of introducing directing groups into the substrates could be saved.Through screening the reaction conditions,such as catalyst,oxidant,base,solvent,temperature and reaction time,etc.,two different tandem cyclization reactions leaded by phenylnitrilium or amide intermediates was achieved,while different kinds of cyclic compounds was obtained,including derivatives of9H-fluoren-9-imine,phenanthren-9(10H)-imine,9-fluorenone and phenanthren-9(10H)-one.In addition,the applicability and mechanism was also explored.