Amination Of Organic Pinacol Boronates

Organoborates are important organoboron compounds with stable chemical properties,abundant species and wide application.In recent years,organoborates developed very fast,and the research on pinacol boronates are favored by scientists.Up to now,the synthesis methods of pinacol boronates are numerous,but in comparison,there is still much room left in exploring the conversion of pinacol boronates,especially in the amination reaction.In this thesis,the amination of organoboron compounds was summarized firstly,then the amination of organoboron through 1,2-migration process has introduced in details,and the shortcomings of the amination of pinacol boronates were pointed out.A new amination reagent was developed to be applied in the amination of pinacol boronates.The main research results of this thesis are as follows:1.A new amination reagent?H₂N-DABCO?was developed.DABCO was introduced into the developed amination reagent as the leaving group in^-Nu-LG,which resulted to a good stability and leaving ability of the amination reagent.According to the literature report and the actual needs,the synthetic procedure for the amination reagent was modified,in which the step to remove impurity by THF was added and the amount of HI was changed.Finally,the target amination reagent was prepared efficiently.The activity of the new amination reagent was tested,and the result revealed that it had good amination activity for pinacol boronates.2.H₂N-DABCO as amination reagent was successfully applied to the amination of pinacol boronates.THF was used as a solvent while KO^tBu as a base.In the presence of H₂N-DABCO,the amination of alkyl and aryl borate occurred quickly under the mild conditions.In addition,olefins and diboronates were well tolerated in the reaction system.Meanwhile,stereospecificity experiment revealed that chiral pinacol boronate 1av could undergo amination under the optimal conditions to achieve the chiral product 2av with complete retention of configuration,which further demonstrated a 1,2-metalate rearrangement process in this amination.