Synthesis And Exploration Of New N-Heterocycle Carbenes

The dissertation put forward the model of 2 new N-Heterocyclic Carbenes(NHC) based on the traditional NHCs. Corresponding NHCs have been synthesized and some key problems also have been solved during the synthesis. Contents of this thesis contains mainly the following two parts:The first part is the synthesis and exploration of 1,3,4-thiadiazole pre-NHCs. We synthesized 9 achiral and 3 chiral 1,3,4-thiadiazole pre-NHCs by adjoin the different fragments. After a comprehensive filterating of the reaction conditons, these catalysts were used to catalyze the synthesis of α-amino boric acid. Compared with the traditional NHCs, new NHCs did not show a good result.The second part is the skeletal synthesis of hexatomic NHCs. Since the main intermediates, ortho-substituent diaryl N-(tert-butylsul?nyl) ketimines, can’t be synthesized in the traditional way of heating. To sovle this problem, the conditions(Lewis acid, temperature and equavelant) were carefully studied. Finally, we foud the optimum parameter that could successfully help us obtain not only ortho-amino substituent but also ortho-nitro substituent diaryl N-(tert-butylsul?nyl) ketimines under microwave assistance. This method presents great advantages to conventional heating because it can be effective to the less reactive compounds. No racemization was observed by chiral HPLC during the reaction.