Visible-light-induced Formal [2+3] Cyclization And Asymmetric Allylation Of Glycine Esters

In the past ten years,visible light-mediated photoredox catalysis has emerged as a powerful tool for organic synthesis under very mild and environmentally benign conditions.Recently,photoredox catalysis has become an attractive method to trigger the C_sp3–H functionalization of amines.However,the majority of such studies have been focused on the functionalization of?-C_sp3–H bonds in tertiary amines,whereas the use of secondary amines as substrates,is scarcely reported.Accordingly,the theme of this thesis is focused on visible light-driven?-C_sp3–H functionalization of glycine derivatives.The main achievements realized by author included:1.A metal-free aerobic oxidative dehydrogenative formal[2+3]cyclization of glycine esters with?-angelicalactone has been accomplished via the synergistic combination of photoredox catalysis and acid catalysis.This protocol provides straightforward and facile access to a series of substituted?-lactams at room temperature under an air atmosphere.Moreover,the reaction could be carried out on a gram scale.The mild conditions as well as the use of cheap substrates and catalyst make this protocol very attractive for further synthetic applications.2.An asymmetric oxidative C_sp3-H allylation of glycine esters has been accomplished involving an initial visible light-driven oxidative imine formation,followed by BINOL derivative-catalyzed asymmetric allylation.This process represents an efficient and facile approach to a series of chiral allylic glycine esters at room temperature under an air atmosphere.Chiral allylic glycine esters can be generated in good yields with excellent regio-and enantioselectivities.