| The [2+2] cycloaddition of olefins is the most versatile and efficient method forsynthesizing fourmembered-ring skeletons and has been applied widely in natural products’intermediates synthesis. Bringing two π bonds into close proximity with the correctorientation is a key step in the promotion of [2+2] cycloaddition reactions in a regio-andstereoselective manner with a high rate. In order to achieve this goal and promote this reactionof photocatalytic styrypyridines derivatives [2+2] dimerization reactions in liquid and solidform, some literatures have been reported that could use various confined media, such ascyclodextrins, calixarenes, molecular sieve and zeolites. However, studying of these reactionsin gel state is very rare. So pursue the photodimerization reaction in gel state would injectnew vitality for the cycloaddition.In this paper a series of acylated cyclodextrins compounds (B1-B6) were designed andsynthesized as organogelators. The compounds were characterized by1H NMR,13C NMR,FTIR spectrum and elemental analysis. The gelation ability of the organogelators was testedin various solvents such as esters, amines, aliphatic hydrocarbons, aromatic hydrocarbons,alcohols, organic acids, etc. To futher understand the morphologies of the gels, SEM skill wasadopted. It was investigated the microstructure of the gels was affected by the solvents andthe substituents.Three photodimerization reactions of trans-styrypyridines derivatives (A1-A3) in gelwere pursued. The interactions between the gel and photoreaction substrates were conductedto the photoreaction in gel state, it was found that the products partially isomerize to thecorresponding cis isomers, furthermore synHT dimerization products as the selective productof the trans-4-strypyridines’photoreaction, and in the trans-2-strypyridines’photoreaction thebenzoquinoline was selectively producted. We can say that the acylated cyclodextrins havecertain selective advantage to the products in gel state. |
PDF Full Text Request