| Sonogashira and Suzuki coupling reactions catylazed by transition metals are effective methods to form C-C, play an important role in organic synthesis and pharmaceutical chemistry. As experimental results show, substituents (electron-donating and electron-withdrawing) attached to benzene ring can affect the yield in coupling reactions.π-πinteraction as a kind of noncovalent interactions, exists widely in cyclophane structure of chemical and biological systems. Research shows that substitutent effects can influence the strength ofπ-πinteraction, which could be well tuned by introducing different substituents into the interactive benzene rings.It is fewly reported howπ-πinteraction and substitutent effects affect coupling reactions catalyzed by transition metals. Therefore, we design dibromo-dithia[3.3] paracyclophanes contained transannularπ-πinteraction to be substrates, introduce different eletronic effect (electron-donating or electron-withdrawing) substituents onto clophane unit, systematically investigate effect ofπ-πinteraction and substitutent effects on Sonogashira and Suzuki coupling reactions. The concrete work lists as follows:1. We systematically investigated effect ofπ-πinteraction and substitutent effects on Sonogashira coupling reaction by studying the coupling reaction between substituents(R=H, NH2, OCH3, NO2, CN) dibromo-dithia[3.3]paracyclophanes and p-methoxyphenylacetylene. The single-coupling products and bi-coupling products were characterized by 1H NMR,13C NMR and elemental analysis. In addition, the strutures of CN substituent products were testified by X-ray diffraction techniques. Experimental results show the product yields of regardless of electron-donating(R=NH2, OCH3) or electron-withdrawing(R=NO2, CN) substituted cyclophanes are higher than no substituted cyclophane. The substituted cyclophanes are more reactive. Substitutent effects inπ-πinteraction increase the yield in Sonogashira reaction, what has no relationship with eletronic effect of substituents.2. We systematically investigated effect ofπ-πinteraction and substitutent effects on Suzuki coupling reactions by reacting substitutented dibromo-dithia[3.3]paracyclophanes with 4-methoxyphenylboronic catalyzed by Pd.All the coupling products were characterized by 1H NMR,13C NMR and elemental analysis. the structures of OCH3 substituent products were testified by X-ray diffraction techniques. Experimental results show, compared with no substituted dibromo-dithia[3.3]paracyclophane, all substituents increase the yield in Suzuki coupling reaction, which also has no relationship with eletronic effect of substituents. |
