Asymmetric Amination Of Cyclohexanone Catalyzed By Chiral Br?nsted Acid

Chiral Br nsted acid catalysts have been booming in recent years.In the presence ofwater and oxygen, the catalysts can effectively maintain the catalytic activity,so that theycan be saved and operated easily. And chemists are very concerned about chiral Br nstedacid catalysts. In the number of chiral Br nsted acid, the chiral binaphthol phosphatecatalysts become an attractive emerging catalyst with wide range of applications.It is significant to synthesize stereoselective compounds with C-N bond from avail-able starting materials in organic chemistry, and molecules with C-N bond play the keychiral role in many important compounds. As we all know, it is simple and effective fordirectly asymmetric addition of the chiral carbon center to the nitrogen in many ways ofbonding method by chiral carbon atoms and nitrogen atoms. In this thesis the catalyticenantioselective amination reactions of cyclic ketones using azodicarboxylates as thenitrogen source with BPI as the catalyst are presented,and this thesis involves thefollowing parts:First of all, we designed and synthesized chiral BINOL-derived Phosphorus imideBPI, which was first introduced with the second chiral binaphthol phosphoryl. The novelphosphorus imides catalyst has a dual-axis of symmetry.By the introduction of the stericand electronic effects at3,3’substituent, BPI can be controled effectively,and be appliedto amination reaction.Secondly, we made asymmetric amination of cyclic ketones as a template to studythe five different types of catalyst, including BINOL, chiral BINOL-derived phosphoricacids, catalyst BPI, chiral primary amine cataysts,and hiourea. According to the results,we found that there was a excellent catalytic properties catalyst BPI,and the productgained93%ee.Finally,we documented the asymmetric amination of cyclohexanone with the use ofcatalyst BPI.The influence of solvents,catalyst and temperature to the yields and enantio-selectivities of the adducts was investigated, and a series of encouraging results wereobserved.Heated in the oil bath,the product gained25%yield and96%ee value,while heated in the microwave, the product gained85%the yield and98%ee value at theoptimized conditions.By comparison of experimental results,the reaction time shortenedfrom96hours to90minutes,the yield increased from25%to85%and ee value increasedfrom96%to98%by the application of microwave heating. Microwave heating not onlycan effectively shorten the reaction time, and improve the enantioselectivity and yield ofamination product.Our research provided preliminary results to our work on the asymmetric aminationof cyclic ketones and further studied is currently underway.