Organocatalytic Asymmetric Decarboxylative Reactions Of ?-keto Acids With Cyclic ?-ketiminophosphonates To Access Quarternary ?-aminophosphonates

Due to its particular biological activity,optically active ?-aminophosphoric acid,an important amino acid analogue,has a wide range of applications in biochemistry and pharmaceutical science.Especially,the quaternary ?-aminophosphoric acid is widely concerned by chemists because of its structural specificity.Therefore,many synthetic methods have been developed.However,most of them are synthesis of acyclic ?-aminophosphoric acids.The cyclic quaternary ?-aminophosphoric acids are relatively rare.In this dissertation,the asymmetric decarboxylative Mannich reaction of ?-keto acids with cyclic ?-ketoenmidophosphonates was catalyzed by a novel saccharidederived bifunctional amino-thiourea,and a series of cyclic quaternary carbon-centered ?-aminophosphonic acids were constructed,including five-membered and six-membered ring structures.After the optimizations of reaction conditions,the products were obtained in 78-93% yield with 90->99% enantioselectivity,and the absolute configuration of 3i was determined by X-ray diffractometer.