The Research On Photochemical And Electrochemical Aromatic C-N Borylation

Aryl boronate esters are important building blocks in organic synthesis,which have found wide applications in material science and medicinal chemistry.Traditional synthetic methods of aryl boronate esters involve electrophilic borylation of aryl Grignard or lithium reagents with harsh reaction conditions and narrow functional groups tolerance.Afterwards,various aromatic borylation transformations have been developed towards the synthesis of aryl boronate esters.However,as two essential aromatic C-N compounds,the borylation of arylhydrazines and nitroarenes still remains unexplored.In recent years,with increasing attention to sustainable chemistry,photochemical and electrochemical organic reactions have gained rapid development.The thesis summarized the recent progress on the aromatic C-B bond formation,C-N bond transformation of arylhydrazines and C-N bond transformation of nitroarenes,and explored the photochemical and electrochemical borylation of arylhydrazine hydrochlorides and nitroarenes.The results obtained are shown follows:1.The electrochemical borylation of inexpensive,readily available and stable arylhydrazine hydrochlorides has been achieved,employing ambient conditions in the absence of transition metal catalyst and additional oxidant.This transformation provides a simple and effective method for the synthesis of aryl boronate esters and enriched the aromatic C-N bond borylation.2.The photochemical borylation of arylhydrazine hydrochlorides has been developed using cheap and easily available organic dye as the photocatalyst under ambient conditions in the absence of transition metal and additional oxidant.In general,higher yields of borylated products were obtained in photochemical borylation than electrochemical borylation.This transformation provides another prompt method towards the synthesis of aryl boronate esters from arylhydrazine hydrochlorides.3.We have achieved the electrochemical borylation of nitroarenes for the first time.This transformation provides an efficient and practical method for the preparation of aryl boronic esters in moderate to good yields with a good tolerance for a broad range of functional groups.The direct utilization of the “synthetically upstream” nitroarenes in borylation transformation would substantially impact the conventional processes for synthesizing functionalized arenes.