Synthesis Of Chiral Ligand Derived From Natural Camphor And Its Application

Camphor and its derivatives are important chiral substances and organic chemical intermediates, mainly used in medicine, chemical and light industry .Asymmetric synthesis in organic chemistry has become one of the most active areas and one of the high-tech industrial organic synthesis. The strategies of using chiral auxiliary in asymmetric synthesis play an important role in the synthesis. Since camphor is a natural optical activity of chiral natural products, low cost, ince camphor is a chiral natural product with natural optical activity, and it is cheap, what's more, its sources are abundant, the asymmetric oxidation of chiral source has been a hot research topic, so the research of their synthesis has important theoretical and practical value.We prepared a chiral ligand from the natural D-camphor after sulfonation, chlorination, coupling, reduction reaction. Firstly, the natural camphor in concentrated sulfuric acid carried to acetic anhydride, due to the formation of the products is a natural process of crystallization, it is crucial to found the factors to affecting the crystallization. In this paper, I will give the effect of feeding method and feed ratio to the yield.We found that the camphor was first dissolved in acetic anhydride, and then slowly dropped to the concentrated sulfuric acid, what method was the best sulfonation reaction and the best feed ratio of camphor and sulfuric acid was 1.0 : 1.2, the chemical yield was from 46.6% to 68.3%, then the camphor sulfonic acid was not stick and easy to handle .Then, the camphor sulfonic acid with thionyl chloride in chloroform carried out the reaction, PCl5 was used instead of SOCl2 as the chlorinating agent in it, because it followed with the severe reaction of PCl5, whose produre must be carried in 0℃ below. And post-processing is a bit trickier, and often local overheating and release some toxic gas. Then the optimum feed ratio was determined.By the camphor chloride and chiral amino alcohol condensation reaction to produce a kind of amide (compound 95), and determine the optimal reaction molar ratio. And then restore the previous step reaction products synthesized a novel chiral ligand (compound 96), selected the moderate NaBH4, and get the best amount of it. When the feed ratio n (reactants): n (NaBH4) = 2, the yield is 70.6%.The successful synthesis of chiral ligands(compound 96), the oxidation of sulfides into their chiral sulfoxide enantioselective catalytic properties were studied, obtained 65.2% chemical yield and 35.2% ee, and showed catalytic activity and poor asymmetric effect.In the hands of naturally occurring sources, L-amino acids are one of most important category, and L-glutamate is the most widely used. L-pyroglutamic acid was obtained by L-glutamate which was heat and dehydrated. L-pyroglutamic acid is not only cheap but easy to get, and nitrogen-containing heterocycles with five-and two-functional group was involved. L-pyroglutamic acid is widely used as chiral biologically active natural and non-natural synthesis of chiral substances, such as in chiral pharmaceutical, pesticide product development and so on. The development of L-pyroglutamic acid as chiral source potential in asymmetric synthesis will continue to show.We focus glutamate derived from chiral ligands for the synthesis of a trial, the successful synthesis of intermediate(compound 96), but the reaction in the next, because of the failure of synthesis of Grignard reagent, the final product could not be obtained.