Pyridine Synthesis Of Double-helix Molecular Link Bridge

Recently ,extensive attention has focused on helical molecules specially chiral double helical molecules on account of their unique structural features and great significance in bionics synthesis as well as their potentialities of optical and electronic use .Though ,some double helical recemates derived from the separate molecule ligand strands complexed with metal ions were reported , it is very difficult to synthesize the type of intramolecular double-helical compound with optical activity and. graceful structure and without complexed metal ions in laboratory. To the best of our knowledge , most of the double helical molecules reported are formers ,and most of them are recemates.In this thesis ,based on numerous literature investigation and the preceding research in our laboratory, a new type of intramolecular double-helical compound with optical activity , in which 2,2'-bisubstituted-l,l'-binaphthyl and meta-pyridine bridges were connected with linear ethynyl was designed and its systhesis was reseached.In the second chapter , the synthesis of 2,2'-biethynyl l,l'-binaphthyl was investigated and through compared research a rational synthesis route was established. By use of commercially available (R)- (2,2' -bihydroxy -1,1'-binaphthyl),and five steps were passed ,which were esterification, substitution, bromization, hydrolization and special wittig reaction, 2,2'-biethynyl 1,1'-binaphthyl with optical activity was obtained successfully.In the third chapter , in order to synthesize the target molecule , two systhesis routes were designed and investigated, which were separately outramolecular and intramolecular coupling closing-cycle reactions routes. The experiments results showed that, though the outramolecular closing-cycle reactions route was brief, its defect was that there were more reaction points in the closing-cycle reaction, which made the reaction result in complicate mixtures, which were very difficult for separated and therefore the formation of the target molecule was unable to be identified. But the target molecular was obtained successfully through the intramolecular coupling closing-cycle reactions route. During this route , seven steps were used ,which included pyridine induction catalyzed by (Ph3P)4Pd-CuI, introduction and outraduction of protecting group and intramolecular closing-cycle reaction under pseudo- high -dilution condition, and the intramolecular double-helical target molecule with plus helical chirality was obtained finally.So, in this thesis , a new type of intramolecular double-helical compound with optical activity , in which 2,2'-bisubstituted-l,l'-binaphthyl and meta-pyridme bridges were connected with linear ethynyl was designed and synthesized successfully . The structrures of all new intermediates and the target molecule were identified by high-resolution MS, 1HNMR, 13CNMR, DEPT special measurement and elemental analysis .