A widely varying range of products in reactions of C6F5BrF2, C6F5IF2, and C6F5IF4 with Lewis acids of different strength
摘要:
The relative fluoride donor ability: C6F5BrF2 > C6F5IF2 > C6F5IF4 was outlined from reactions with Lewis acids of graduated strength in different solvents. Fluoride abstraction from C(6)F(5)HaIF(2) with BF3.NCCH3 in acetonitrile (donor solvent) led to [C(6)F(5)HaIF-(NCCH3)(n)][BF4]. The attempted generation of [C6F5BrF](+) from C6F5BrF2 and anhydrous HF or BF3 in weakly coordinating SO2CIF gave C6F5Br besides bromoperfluorocycloalkenes C6BrF7 and 1-BrC6F9. In reactions of C6F5IF2 with SbF5 in SO2CIF the primary observed intermediate (F-19 NMR, below 0 degrees C) was the 4-iodo-1,1,2,3,5,6-hexafluorobenzenium cation, which converted into C6F5I and 1-lC(6)F(9) at 20 degrees C. The reaction of C6F5IF4 with SbF5 in SO2CIF below -20 degrees C gave the cation [C6F5IF3](+) which decomposed at 20 degrees C to C6F5I, 1-iodoperfluorocyclohexene, and iodoperfluorocyclohexane. Principally, the related perfluoroalkyl compound C6F13IF4 showed a different type of products in the fast reaction with AsF5 in CCl3F (-60 degrees C) which resulted in C6F14. Intermediate and final products of C(6)F(5)Hal(n-1) (n = 3, 5) with Lewis acids were characterized by NMR in solution. Stable solid products were isolated and analytically characterized. (C) 2008 Elsevier B.V. All rights reserved.
以高收率制备了以前未知的多氟环己烯基和无环全氟烯基碘四氟化物。使用XeF 2 -NbF 5在aHF中从五氟碘苯制得全氟环己-1-烯基碘四氟化物。C 6 F 5 I与较弱的氟氧化剂XeF 2 -BF 3在1,1,1,3,3-五氟丁烷(PFB)中的反应生成C 6 F 5 IF 2,全氟环己-1,4-二烯基碘二氟化物,C 6 F 5中频4,全氟环己-1,4和1,3-二烯基碘四氟化物作为平行反应路线上的中间产物。全氟链烯基碘化物的顺式和反式(CF 3)2 CFCFCFIFI与XeF 2 -BF 3在PFB中反应,得到相应的全氟链烯基碘化物四氟化物,顺式和反式(CF 3)2 CFCFCFIF 4。如从C 6 F 13制备C 6 F 13 IF 4所证明的那样,甚至该试剂也可以氟化全氟烷基碘。I.通常, 环状或无环全氟链烯基碘化合物R F IF n中的CFCIF n片段(n = 0、2或4)没有转化为