| As a member of chalcogen elements,tellurium has been widely used in organic synthesis,pharmaceutical chemistry,biochemistry,material science etc.At the same time,tellurium-containing compounds are also important intermediates in the field of synthesis,with unique chemical properties and biological activities.Organic tellurium compounds are easily ignored substances,and there are few reports on their catalytic properties.However,the study of their catalytic properties may bring some unique discoveries,which is of great scientific significances.This thesis reported the thermal-driven deoximation reaction,the photo-driven deoximation reaction and the cross dehydrogenation coupling reaction catalyzed by organic tellurium compounds using molecular oxygen as oxidant.The main contents are as follows:1.The thermal-driven organotellurium catalytic oxidative deoximation reaction was studied.The solvent-free reaction was performed using 2.5 mmol%(PhTe)2 as catalyst and oxygen as oxidant.Its unique free radical reaction mechanism was verified by the parallel experiments and XPS analysis.Compared with traditional methods,this method avoids the use of organic solvents,and has the advantages of good yield,wide substrate adaptability,and simple operation.2.The photo-driven organotellurium catalytic oxidative deoximation reaction was studied.In this reaction,1 mmol%(PhTe)2 was used as catalyst,oxygen was used as oxidant and blue LEDs was used as light source to drive the process.The free radical reaction mechanism was confirmed by control experiment.Compared with the thermal-driven deoximation reaction,the reaction conditions are much milder.In this reaction,blue light could break the Te-Te bond accurately to generate the active free radical catalytic intermediates without damaging the fragile substituents(e.g.heterocycles)in substrates.3.The cross dehydrogenation coupling reaction catalyzed by organic tellurium with molecular oxygen as oxidant was studied.The cross dehydrogenation coupling of sp2-sp3 bond between two carbon atoms can be carried out by using 5 mmol%(PhTe)2 as catalyst,p-toluenesulfonic acid as catalyst and oxygen as oxidant,and the target product can be obtained in a nice yield.Compared with the existing methods,good regio-selectivity,good substrate adaptability and clean reaction system are the advantages of this method to achieve the sp2 and sp3 C-C cross coupling. |
