Novel SN2 ring-opening reactions of 2- and 2,2-substituted thiiranes with thiols using Na+-exchanged X-type zeolite or triethylamine in methanol
作者:Hiroshi Takeuchi、Yasuhisa Nakajima
DOI:10.1039/a804879g
日期:——
the concentration and nucleophilicity of 2, the reactivity of 1 towards 2 and so on. This suggests that the reactions using Na+-zeolite X or Et3N proceed via a zwitterion or an ion-pair intermediate, respectively, by an SN2 attack on 1 of 2, having enhanced nucleophilicity due to the basic catalysts. The reactions using Na+-zeolite A-3 or H+-zeolite X in MeOH or benzene and that using H2SO4 in benzene
使用Na +交换的X型沸石(Na + -沸石X)或在MeOH中的Et 3 N生成烷基硫代乙硫醇3。但是,2-苯基噻烷1c的反应不再具有区域特异性,在C-3和C-2处的开环给出3和4。产物的产率受催化剂,溶剂极性,2的浓度和亲核性,1对2的反应性等影响。这表明使用Na +-沸石X或Et 3 N的反应分别通过两性离子或离子对中间体通过S N进行。2攻击2的1,由于碱性催化剂而具有增强的亲核性。还研究了在甲醇或苯中使用Na +沸石A-3或H +沸石X以及在苯中使用H 2 SO 4的反应。