Vicinal bromofluoroalkanes: their regioselective formation and their conversion to fluoroolefins
作者:Hiroaki Suga、Takeshi Hamatani、Yves Guggisberg、Manfred Schlosser
DOI:10.1016/s0040-4020(01)86762-4
日期:——
The reaction of alkenes with N-bromosuccinimide and triethylamine tris(hydrofluoride) produces vic-bromofluoroalkanes (1) with high yields. As long as the addition to the double bond is sterically unhindered, bromine and fluorine get attached with very high regioselectivity, the latter halogen occupying the more substituted, carbocation stabilizing position. 2-Fluoro-1-alkenes give 1-bromo-2,2-di-fluoroalkanes
烯烃与N-溴代琥珀酰亚胺和三乙胺三(氟化氢)的反应可高产率地生成vic-溴氟烷烃(1)。只要双键的加成在空间上不受阻碍,溴和氟就会以非常高的区域选择性连接,后者的卤素占据了取代度更高的碳阳离子稳定位置。2-氟-1-链烯烃产生1-溴-2,2-二氟链烷(4)。较重的卤素可被移除由碱促进脱氢氟化,得到氟代烯烃(2,或通过还原与氢化三丁基锡),导致单或difluoroalkanes(例如,5)。