Synthesis Of New O-carboryne Precursor And Its Reactivity Toward Furans And Thiophenes

Carboranes are generally accepted as polyhedral boranes with one ormore boron vertices being replaced by carbon. Carboranes exhibitfascinating features such as spherical geometry and hydrophobicmolecular surface, remarkable thermal and chemical stability, which havebeen found extensive applications in medicals, polymers and catalysts. Asa very reactive intermediate, carboryne can react with various substratesto generate functionalized carboranes conveniently. So it is meaningful toinvestigate the new carboryne precursors and to study their reactivity. Thecontents mainly concluded the three parts:Chapter1describes the synthesis methods and the basic propertiesof Carboranes and gives an overview on the recent advances in the fieldof reactions of carborynes. As a reactive intermediate, o-carboryne reactsreadily with alkenes, dienes, alkynes, aromatics or heteroaromatics in [2+2] and [4+2] cycloaddition as well as ene reaction fashions. And alsoo-carboryne can undergo insertion of sp3α-C H bond of aliphatic ethersor sp2C H bond of ferrocene. These can be formed a series of functionalized carboranes. These pioneering reactions promise a newstrategy for generating functionalized carboranes that are not ready toaccess by known methods.Chapter2describes synthesis of1-I-2-TMS-1,2-C2B10H10,1-OTs-1,2-C2B10H11and1-OTf-1,2-C2B10H11. These compoundssynthesis methods are simple, highly efficient and easy post-processing,which makes theirreactivity can be further studied.Chapter3describes the comparison of reactivity between the threenewly synthesized and three known carboryne precursors. The reactivityof1-OTf-1,2-C2B10H11is the highest in cycloaddition reaction witharenes. After further study, we found that1-OTf-1,2-C2B10H11can reactefficiently with furans with excellent [4+2]/[2+2] cycloadditionselectivity and furan/phenyl ring selectivity. The corresponding[4+2]/[2+2] cycloaddition selectivity is lower in the reaction withthiophenes...