Selective bromofluorination of alkenes with 1,3-dibromo-5,5-dimethylhydantoin and silicon tetrafluoride
作者:Makoto Shimizu、Yuko Nakahara、Hirosuke Yoshioka
DOI:10.1039/c39890001881
日期:——
Alkenes have been converted into the corresponding bromofluorides by reaction with 1,3-dibromo-5,5-dimethylhydantoin (DBH) and silicontetrafluoride in 1,4-dioxane in a highly regio-, stereo-, and chemo-selective manner.
ALIPHATIC VICINAL FLUOROBROMIDES SOME PREPARATIONS AND REACTIONS
作者:F. L. M. Pattison、D. A. V. Peters、F. H. Dean
DOI:10.1139/v65-223
日期:1965.6.1
The addition of "BrF", using N-bromoamides in anhydrous hydrogen fluoride, to a number of aliphatic alkenes has been studied. As expected, the bromine atom in the resultant vicinal fluorobromides exhibited relatively low reactivity in nucleophilic and hydrogenolytic reactions.
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.
yields. These [3,3]-sigmatropic rearrangements are diastereoselective giving trans-configured double bonds, exclusively. Corresponding esters derived from (Z)-2-fluorocyclododec-2-enol (22), did rearrange to yield mixtures of diastereomers much less selectively. Also 2-fluorodec-2-enol (6), which was prepared by rearrangement of 2-fluoro-2-octyloxirane (5) with TMSOTf and triethylamine, was successfully
1,1,3,3,3-Pentafluoropropene-diethylamine complex (PFPDEA) has been found useful as a fluoride source in halofluorination reactions of various olefins. Reactions proceeded with PFPDEA and N-halosuccinimide (NXS, X = Br, I) or 1,3-dibromo-5,5-dimethylhydantoin (DBH), as sources of electrophilic halogens, in a regioselective manner. (C) 2012 Elsevier B.V. All rights reserved.