Effect of solvent nature on the regioselectivity of the reactions of pyridinium ylides with E-1,2-di(alkylsulfonyl)-1,2-dichloroethene. From the reaction of 1,3-dipolar cycloaddition to the reaction of nucleophilic addition–elimination (AdN–E1,5)
作者:Natalia E. Dontsova、Vladimir N. Nesterov、Anatoliy M. Shestopalov
DOI:10.1016/j.tet.2013.03.098
日期:2013.6
The effect of solvent nature on the reactions of pyridinium ylides with E-1,2-di(alkylsulfonyl)-1,2-dichloroethene was investigated for the first time. It was found, that in aprotic solvents (CHCl3, DMF, CH3CN) these reactions take place as a 1,3-dipolar cycloaddition (1,3-DC) followed by double elimination with the formation of substituted 1,2-di(alkylsulfonyl)indolizines. In a protic solvent (EtOH)
首次研究了溶剂性质对吡啶鎓叶立德与E -1,2-二(烷基磺酰基)-1,2-二氯乙烯的反应的影响。已经发现,在非质子溶剂(CHCl 3,DMF,CH 3 CN)中,这些反应以1,3-偶极环加成(1,3-DC)的形式发生,随后被双重消除并形成取代的1,2-二(烷基磺酰基)吲哚嗪。在过量的Et 3 N存在下,在质子溶剂(EtOH)中并加热,取代的吡啶鎓盐与E -1,2-二(烷基磺酰基)-1,2-二氯乙烯的反应同时作为1,3- DC和作为加法-消除法(Ad N –E 1,5)并导致形成1,2-二(烷基磺酰基)吲哚嗪和4,5-二(烷基磺酰基)呋喃。