The Synthesis Of Amino Acid Derivatives Chiral Guanidine Salt And Their Application In Asymmetric Vinylogous Reactions

Over the past several years, organic asymmetric catalysis based on small molecules has got significant attention on chemists, since the method showed wide range of applications and efficiency on the complex natural products. Small organic molecule asymmetric catalysis spares series merits on metal catalysis or enzyme catalysis, such as plentiful sources, easy to operate, non-toxic, etc. Besides, organic catalysis do the meaningful function as the bridge on connecting all kinds of catalytic types. This article outlines the synthesis of amino acids derived guanidine salt catalyst, and it's application study on several reactions, such as Vinylogous Amination and Vinylogous Aldol reaction.1. Study on the synthesis of guanidine salt catalyst derived from amino acidsIn this paper, a class of new catalysts were synthesized from derived amino acids, and it's successful application on small organic molecule asymmetric reaction. Firstly, through on a whole analysis on it's structure and optimization on synthetic route, amino acids guanidinium chiral organic catalysts are obtained. The catalyst choose an L- amino acids as initial substrate, through 10-step to give the desired catalyst product, the total yield reach to 28.3%. To our delight, the catalyst owned multi-functional group which can form several H-Bond with corresponding substrate, it's distinct spatial structure is good for chiral control on asymmetric synthetic processes. Furthermore, the catalyst can be improved from several chemical sites, wide range of catalyst with different substituents can be synthesized.2. Asymmetric amination reaction for 4- nitro isoxazole and diethyl azodicarboxylateThis paper studied a novel asymmetric vinylogous amination reaction of isoxazole and 4-nitro-diethyl azodicarboxylate, to give the isoxazole core skeleton structure which contains ?-amino as the aim product. Surprisingly, a 96% high yield and 93% ee were got with the application of polyfunctional guanidine chiral catalysts. This is the first application on asymmetric vinylogous amination reaction, achieved fabulous enantioselectivity.3. Asymmetric vinylogous aldol reaction for 4-nitro-isoxazole and paraformaldehydeBased on the study of asymmetric vinylogous amination reaction of 4-nitro-isoxazole and diethyl azodicarboxylate, the paper further studied 4-nitro-isoxazole and paraformaldehyde's asymmetric vinylogous aldol reaction, again, an excellent result obtained with the corresponding polyfunctional guanidine chiral catalysts(97% yield, > 97% ee).