无需金属和碱的催化,以1,4-二芳基取代-1,3-丁二炔与Na2S·9H2O为反应底物,80℃下DMF中合成了2,5-二芳基噻吩类化合物,考察了反应物苯环上电子效应和空间位阻对硫杂环化反应的影响.结果表明:反应物苯环上的吸电子或电子取代基团均对反应产物的分离产率影响不大;空间位阻较大的反应底物硫杂环化反应的收率略有降低,各种目标化合物产率为88%~100%.
2,5-Diarylated thiophenes were synthesized via metal-free,base-free sulfur heterocyclization of 1,4-diaryl-1,3-diyne with Na2S·9H2O in DMF at 80 ℃ with a yield of 88%~100%.The influences of electronic effect and space hindrance on the sulfur heterocyclization were investigated.The results showed that the inconspicuousness difference was observed in isolated yield while the substituents containing electron-donating or electron-withdrawing in aryl-position of reactants were used,but slightly lower yield while the reactants with steric hindrance were tested.