Chiral Phosphate Catalyzed Asymmetric Amination Of 3-Aryl-2-benzofuranones

The formation of enantioselective C-N bonds at the α-carbon of carbonyl compounds is an important class of chemical reactions.These chemical reactions can produce chiralα-aminocarbonyl compounds,which exist in a variety of natural products with important biological activity.So this kind of reaction received extensive attention.However,the existing catalytic synthetic methods require long reaction time and high catalyst dosage,which greatly limits the development and application of such compounds.The use of a small amount of catalyst to efficiently synthesize important chiral molecular structures through asymmetric conversion has been one of the unremitting pursuits of organic chemistry researchers.In the field of chiral catalysis,phosphoric acid is an excellent catalyst capable of catalyzing various types of reactions.At the same time,the emergence of metal phosphate has a positive effect on the production of highly stereoselective products.The main research content of this thesis was to use chiral metal phosphate as catalyst,3-aryl-2-benzofuranones and dibenzyl azodicarboxylate as reactants to synthesize highly enantioselective 3-amino-2-benzofuranone compounds by asymmetric amination.In this paper,the chiral phosphoric acids and their metal salts with different frameworks were first selected to determine the optimal catalyst.Then the variables such as the amount of catalyst and the reaction solvent were investigated in sequence,and the optimal reaction condition was finally determined.Under this condition,the generality and limitations of benzofuranone substrates were further investigated.The study found that this catalytic method can use a very small amount of catalyst for rapid catalysis and has good substrates compatibility.A total of 22 3-amino-2-benzofuranone compounds with different substituents were synthesized in this thesis.Most of them had good enantioselectivities and excellent yields.Among them,the enantioselectivity was up to 99% and the yield was up to 99%.The series of 3-amino-2-benzofuranone compounds synthesized in this thesis had good enantioselectivities and excellent chiral skeleton,which complement existing chiral molecules.The structure of chiral α-aminocarbonyl compounds formed by asymmetric amination at the α-position of carbonyl compounds is important skeleton of natural medicine,which is helpful to the synthesis of important medical compounds.