Several spiro 2-pyrrolidin-5-ones were obtained by a two-step procedure from N-substituted succinimides, involving spiro cyclisation of N-acyliminium ion intermediates in refluxing trifluoroacetic acid; in all cases cyclisation utilised a tethered aromatic π-nucleophile, and ring-closure followed 5- or 6-exo-trig pathways.
通过两步程序从N-取代的琥珀
酰亚胺中获得了几个螺2-
吡咯烷基-5-酮,包括在回流的
三氟乙酸中螺环化N-
酰亚胺离子中间体。在所有情况下,环化均利用系留的芳香族π-亲核试剂,且闭环遵循5或6 -exo-trig途径。