The Design And Synthesis Of Double Helicate With Chiral 2, 2'-Binaphthyl Template

It is one of the greatest achievements in life sciences that scientists had testified the structure of DNA by X-ray diagram and chemical apparatus in the fifties of the twentieth century. However, it is still a great challenge for chemists to synthesis double helicate molecules in laboratory. Recently, optically active cyclophanes, such as helical molecules and three-dimensional, cagelike cyclophanes have been the subject of extensive investigation from the standpoints of structural chemistry and material science. The fundamental sources of the interest in cyclophanes include the conception of novel, aesthetically pleasing and interesting structures, the challenge of synthesizing them, and the study of their properties once they had been prepared. Their unique structural features (π-conjugated, helicity) indicate their potential applications in optics and electronics. The familiar method reported to build the double helical molecules is forming complex compounds and self-assembling between the lagands molecule and metal ions. Tough the reaction between lagands and the metal ions are effective for the helicaling process, giving single chiral helicate compound (P:plus or M:minus) selectively are difficult owing to lacking of asymmetric factor to induce the assembly and the isomer speration are tedious.In this thesis, based on the preceding research of our laboratory, a new type of helical molecules, containing 1,1'-binaphthyl unit, the source of chirality and 1,2-bis(4'-iodophenyl)acetylene connected by ethynyl was designed and synthesized successfully and their optical properties were preliminarily studied.In the second chapter, a rational synthetic route for enantiopure 2,2'- diethynyl-1,1'-binaphthyl was established. Enantiopure (R)- or (S)-binapythol can be purchased conveniently and was a good material. From the optically active 2,2'-dihydroxy-1,1'-binaphthyl, through esterification, Kumada coupling, bromization, hydrolization and Wittig elimination reaction, 2,2'-diethynyl -1,1'-binaphthyl was obtained.In the third chapter, compounds (R,P)-50a and (R,P)-50b with double helical structure were designed and synthesized from (R)-2,2'-diethynyl-1,1'-binaphthyl by the introduction of protecting group, the connecting of linking bridges and intramolecular Sonogashira reaction. In the last intramolecular Sonogashira reaction, a syringe pump that can control the dropping rate of reactant solution was used in order to avoid the high concentration of reactant. The high concentration of reactant will produce intermolecular Sonogashira and Eglinton reaction. By using the syringe pump, the yields of the last step of intramolecular Sonogashira reaction were greatly improved. The structures of the new intermediates and target molecules were identified by 1H NMR, 13C NMR, DEPT, IR and the structures of the target molecules were simulated in a computational chemistry way. (R, P)-50a (R, P)-50bTo further study of their properties, the formation enthalpy (ΔH), UV-Vis and circular dichroism (CD) spectra of the target compounds were measured.So, in this thesis, a new type of double helical compouds with novel, aesthetically pleasing and interesting structures, in which two different linkers were connected to the 2- and 2'-positions of a 1,1'-binaphthalene template with ethynyl was designed and synthesized successfully.