Selective Halofluorination of Alkenes with Tetrabutylphosphonium Dihydrogentrifluoride in Combination with<i>N</i>-Halosuccinimide or 1,3-Dibromo-5,5-dimethylhydantoin
Alkenes and their functionalized derivatives were readily converted to the corresponding halofluorides with tetrabutylphosphonium dihydrogentrifluoride as combined with N-halosuccinimides or 1,3-dibromo-5,5-dimethylhydantoin in highly regio-, stereo-, and chemoselective manners. In particular, alkenes having a oxirane or primary hydroxyl group also underwent halofluorination selectively in good yields
Halofluorination of Alkenes Using Dilute Hydrofluoric Acid
作者:Manabu Kuroboshi、Tamejiro Hiyama
DOI:10.1246/bcsj.68.1799
日期:1995.7
Iodofluorination of alkenes was achieved with N-iodosuccinimide, potassium hydrogendifluoride, and 1 M hydrofluoric acid using tetrabutylammonium fluoride as a phase-transfer catalyst. The active fluorinating reagent was shown to be tetrabutylammonium dihydrogentrifluoride by preparing the salt in a different way and by effecting the same transformation under anhydrous conditions. Bromofluorination
使用四丁基氟化铵作为相转移催化剂,用 N-碘代琥珀酰亚胺、二氟化氢钾和 1 M 氢氟酸实现烯烃的碘氟化。通过以不同的方式制备盐并在无水条件下进行相同的转化,活性氟化试剂显示为四丁基二氟化氢铵。烯烃的溴氟化也使用 1,3-二溴-5,5-二甲基乙内酰脲进行。用 DBU 处理 I-F 加合物可立体定向地提供氟烯烃。
Poly-4-vinylpyridinium Poly(Hydrogen Fluoride): A Solid Hydrogen Fluoride Equivalent Reagent
作者:George A. Olah、Xing-Ya Li、Qi Wang、G. K. Surya Prakash
DOI:10.1055/s-1993-25924
日期:——
Poly-4-vinylpyridinium poly(hydrogen fluoride) (PVPHF), containing 35-60% hydrogen fluoride by weight, was prepared as a solid hydrogen fluoride equivalent reagent. PVPHF with 60% hydrogen fluoride by weight was found to be a versatile fluorinating agent for the hydrofluorination and bromofluorination of alkenes and alkynes, fluorination of alcohols as well as other fluorination reactions. Low hydrogen fluoride content PVPHF (3 equivalents of hydrogen fluoride to 1 equivalent of 4-vinylpyridine unit) was also found to be an efficient reagent for bromofluorination of alkenes in the presence of 1,3-dibromo-5,5-dimethylhydantoin. Fluorosulfonic acid-modified PVPHF showed enhanced reactivities for the fluorination of secondary alcohols.
Hydrogenfluoride is a basic fluorinating reagent, but handling it is difficult. For this reason, some modified fluorinating reagents such as HF-pyridine, Et3N-HF, and poly(hydrogenfluoride) complex have been developed. Those reagents, however, still require aqueous work-up procedures which generate hydrogenfluoride. Recently, ionic liquids have received much attention because of the ease in handling