gem-Difluoroolefins bearing homoallylic tosylamido,
hydroxy, or mercapto groups undergo intramolecular nucleophilic
substitution of the nitrogen, oxygen, or sulfur with loss of fluorine
via a 5-endo-trig process, leading to
2-fluoro-2-pyrrolines, 5-fluoro-2,3-dihydrofurans, or -thiophenes in high
yields.
带有同烯丙基对
甲苯磺酰胺基、羟基或巯基团的二
氟烯烃,通过5-内型三元环化过程,在分子内发生氮、氧或
硫的亲核取代反应并脱去
氟,从而高产率地生成2-
氟吡咯啉、5-
氟-
2,3-二氢呋喃或
噻吩。