A reaction of 2,2,2-trihalobenzo-1,3,2-dioxaphospholes with terminal alkylacetylenes proceeds under mild conditions (∼20 °C) and leads to the formation of 4-alkylbenzo[e]-1,2-oxaphosphinine 2-oxide derivatives. The presence of aliphatic substituents in acetylene decreases (as compared to their aromatic counterparts described earlier) regioselectivity of halogenation of benzo fragment in 4-alkylbenzo[e]-1,2-oxaphosphinines: besides predominant 4-alkyl-2,6-dihalobenzo[e]-1,2-oxaphosphinines, minor 2,7- and 2,8-dihalo-substituted 4-alkylbenzo[e]-1,2-oxaphosphinines are formed. An unusual thermal isomerization of 4-alkyl-2-fluorobenzo[e]-1,2-oxaphosphinines to 4-alkylidene-2-fluoro-3,4-dihydrobenzo[e]-1,2-oxaphosphinines was discovered. Molecular and supramolecular structures of some 4-alkylbenzo[e]-1,2-oxaphosphinines were studied by X-ray diffraction analysis.
2,2,2-三卤代苯并-1,3,2-二氧
磷环与末端烷基
乙炔在温和条件下(20 °C~)发生反应,生成 4-烷基苯并[e]-1,2-氧膦 2-氧化物衍
生物。
乙炔中脂肪族取代基的存在降低了 4-烷基苯并[e]-1,2-氧杂膦中苯并片段卤化的区域选择性(与前面所述的芳香族取代基相比):除了主要的 4-烷基-2,6-二卤代苯并[e]-1,2-氧杂膦外,还形成了少量的 2,7- 和 2,8- 二卤代 4-烷基苯并[e]-1,2-氧杂膦。发现了 4-烷基-2-
氟苯并[e]-1,2-氧杂膦与 4-亚烷基-2-
氟-3,4-二氢苯并[e]-1,2-氧杂膦的不寻常热异构化。通过 X 射线衍射分析研究了一些 4-烷基苯并[e]-1,2-氧杂膦的分子和超分子结构。