Studies On The Synthesis Of C-oxetane/alkenyl-o-carboranes And O-carborane Fused Indolines Derivatives

o-Carborane and its derivatives have broad application in organic optoelectronic materials,coordination chemistry,biomedicine etc.,and the selective carbon/boron functionalization of o-carborane is of great significance to promote the development of carborane chemistry and its applications in related fields.Based on the weak acidity of cage C-H bonds of o-carborane,the nucleophilic substitution or transition metal mediated/catalyzed cycloaddition of carboryne for functionalization of cage carbon has been well developed.However,the structure of C-substituted o-carborane derivatives obtained by these methods is relatively single,which cannot meet the needs of complex molecules in biomedicine and other fields.Boron functionalization of o-carborane has been rapidly developed in recent years,and due to the special position of heterocyclic frameworks in medicinal chemistry,thus promoting chemists to develop new methodologies for synthesis of o-carborane fused heterocyclics.Oxidative dehydrogenation coupling strategy is an effective method for construction of o-carborane fused heterocycle with highly atomic economy,which has attracted many attentions from chemists to realize this ideal reaction mode.Based on this point,this paper carried out the research on"Studies on the synthesis of C-oxetane/alkenyl-o-carboranes and o-carborane fused indolines derivatives",the main contents include the following three parts:Part I:The Cu（OTf）₂/NBS promoted cyclization of 1-cinnamyl alcohol-o-carboranes for synthesis of 1-oxetane-o-carborane has been developed.A series of 1-oxetane-o-carborane has been synthesized with 40%～67%yields.It has laid a material and technical foundation for exploring the application of 1-oxetane-o-carborane derivatives in the fields of medicine,materials and optoelectronics,and the 1-oxetane-o-carborane would be an important synthon for designing novel reactions in oxetane chemistry as well as carborane chemistry.Part II:On the basis of synthesized 1-oxetane-o-carborane,using electron-rich arenes as soft nucleophiles,the Cu（OTf）₂/NBS-mediated tandem reaction of 1-cinnamyl alcohol-o-carboranes for the synthesis of C-alkenyl-o-carboranes has been developed.A series of C-alkenyl-o-carboranes has been synthesized with 31%～99%yields.This work provided an alternative strategy for the synthesis of C-alkenyl-o-carboranes,which is an important reference for the synthesis of o-carborane derivatives with diversity.Part III:An iridium-catalyzed selective amination of B（4）-H via oxidative dehydrogenation coupling of B-H/N-H bonds for the synthesis of o-carborane-fused indolines has been developed for the first time.A series of o-carborane-fused indolines have been synthesized with 30%～81%yields,which would be potential candidates for applications in drug discovery,pharmaceutical chemistry and functional materials.This work offers a valuable reference for designing and synthesis of o-carborane-fused heterocycles.