Riedl Zsuzsanna, Kövér Péter, Soós Tibor, Hajós György, Egyed Orsolya, Fábián László, Messmer András
Chemical Research Center, Institute of Chemistry, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary.
J Org Chem. 2003 Jul 11;68(14):5652-9. doi: 10.1021/jo034231a.
2-Arylsulfanyl and 2-benzylsulfanylpyridinium N-arylimides (2) easily prepared from 3-aryltetrazolopyridinium salts (1) with aryl and benzylthiolates, respectively, reacted with various dipolarophiles yielding cycloadducts that underwent transformation to give tetrahydropyrrolo[3,2-b]pyridines (5, 6, and 8) in good yields. A similar rearrangement (formation of 15) was also observed in the case of parent derivatives being unsubstituted in position 2 (12). The abscence of any significant solvent effect, comparison of the sulfur and non-sulfur analogues, as well as the stereoselective nature of the observed ring transformation seem to support a sigmatropic mechanism. Structure elucidation of the products has been carried out by single-crystal X-ray diffraction and (1)H NMR experiments.
2-芳硫基和2-苄硫基吡啶鎓N-芳基酰亚胺（2）分别由3-芳基四唑并吡啶鎓盐（1）与芳硫醇盐和苄硫醇盐轻松制备，它们与各种亲偶极体反应生成环加成物，这些环加成物经过转化后以良好的产率得到四氢吡咯并[3,2-b]吡啶（5、6和8）。在2位未被取代的母体衍生物（12）的情况下，也观察到了类似的重排（形成15）。没有任何显著的溶剂效应、硫代和非硫代类似物的比较以及所观察到的环转化的立体选择性性质似乎支持一个[3,3] - 迁移机理。产物的结构解析通过单晶X射线衍射和¹H NMR实验进行。
