Studies On Visible-Light-Promoted C_sp3-H Functionalization Of Glycine Derivatives: Synthesis Of Unnatural Amino Acids And Post-modification Of Oligopeptides

Unnatural α-amino acids are widely used as important building blocks in organic synthesis and pharmaceutical synthesis.The direct α-C(sp3)-H functionalization of glycine derivatives is one of the most direct and efficient methods for the synthesis of unnatural α-amino acids.However,traditional C(sp3)-H functionalization reactions usually require very harsh reaction conditions(e.g.,excessive oxidant,high temperature,etc.)In the past decade,photoredox catalysis has become a powerful tool in the field of organic synthesis due to its mild reaction conditions and environmental friendly advantages.The main research content of this thesis is centered on the visible lightinduced C(sp3)-H functionalization reaction of glycine derivatives.Accordingly,the main research content of this thesis includes the following two parts:1.A Ce(Ⅲ)catalyzed visible light-induced aerobic oxidative dehydrogenative coupling/aromatization tandem reaction between glycine derivatives and unactivated olefins has been accomplished(Figure 1).This reaction provides a facile method for the rapid synthesis of a series of substituted quinoline-2-carboxylates with a yield of 30-98%under mild conditions(room temperature,air atmosphere,visible light irradiation).The process is noteworthy in that it does not require a photosensitizer or an additional oxidant.Moreover,this method also provides an efficient approach for the post-modification of oligopeptides containing glycine residues.2.A visible light-induced oxidative[3+2]cycloaddition reaction between glycine derivatives and thiirane derivatives has been developed(figure 2).This reaction provides a efficient approach for the rapid synthesis of 1,3-thiazolidine derivatives with moderate to excellent yields(30 to 91%)as well as excellent diastereomeric selectivity(>20:1)under mild reaction conditions.Compared to traditional methods,the presented method has the advantages of mild,atomic economy,and ease of operation.More importantly,this method can also be used for the post-modification of dipeptides containing glycine residues.