Research On The Tandem Reactions Of Oxime Derivatives For The Synthesis Of Fused Nitrogen-containing Heterocycle

Oxime derivatives are versatile and fascinating building blocks in organic synthesis with advantages of easy availability,convenient storage and high reactivity.Due to its reactive N-O bond,oxime derivatives could serve as internal oxidants in the reaction.In recent decades,with the rapid development of transition metal-catalyzed reactions,ketoxime derivatives have achieved tremendous progress in the construction of carbon-carbon bonds and carbon-heterobonds via C-H functionalization.Numerous of nitrogen-containing frameworks could be constructed in a simple fashion.Despite those significant advances,synthetic methods that allow oxime derivatives to construct fused heterocycles remain challenges.Therefore,the development of more types of transformations of oxime derivatives to construct fused heterocycles is highly desirable.In this context,the works on tandem cyclization reactions involving oxime derivatives to construct nitrogen-containing fused heterocyclic compounds have been developed.Those reactions are simple to operate without external oxidants.The details are summarized as follows:In chapter two,we developed a novel strategy to construct thienothiazoles skeleton from oxime esters,elemental sulfur（S₈）,alkynes/aldehydes.This process involves N-O/C（sp³）-H/C（sp²）-H bonds activation,as well as C-S/C-N bonds formation.In the reaction,the oxime esters are employed not only as C2N1 units but also as C4 units to construct fused heterocycles.In chapter three,a novel strategy for the synthesis of 2-aroylthienothiazoles via C-H/N-O bond functionalization of ketoximes is developed.This reaction could be carried out in a metal-free manner without external oxidant,which simplifies the experimental protocol and improves the atom economy of the process.Moreover,the reaction futures broad substrate scope,good functional group tolerance and gram scale test.