The Study Of Asymmetric Photoinduced Electron Transfer Cyclization Reaction

As a focus in organic photochemistry, photoinduced electron transfer reaction is always an important concern of chemists in recent years.The aim of this research is to study the stereocontrol method in PET cyclization reaction. This article synthesized a series of organic molecules which included 9 compounds use phthalimido group as electron acceptor and 12 compounds use benzoyl group as electron acceptor. These compounds were irradiated by 500 W ultraviolet under nitrogen atmosphere in room temperature. After filtration of the photochemical character of these molecules, (L)-N-((3-phthalimido)-propionyl)-proline was selected as an appropriate model reactant.This article developed a series of work on the model reactant. At first, optimized the condition of PET cyclization reaction, such as solvent, reaction time and additive; second, under the optimized condition, the model reactant was mixed with a series of organic bases which included (R),(S)-N,N'-dimethyl-diaminecyclohexane, (L)-prolinol, adamantylamin derivatives and P-CD-NH2. Some conclusions of stereocontrol methods in this pattern of reaction were obtained through analysis and comparison of the ratio of cis- and trans- conformational product: the Steric hindrance of organic bases influenced the stereoselectivity of PET cyclization reaction, the stereoselectivity promoted with the accretion of the volume of the base molecular; in addition, the different stereoselectivity of (L)-N-((3-phthalimido)-propionyl)-proline and (L)-N-((3- phthalimido)-aceryl)-proline in PET cyclization illuminated reactant molecular structure influenced the PET cyclization selectivity.In the finality, the problems requiring further studies are discussed.