Preparation of .beta.,.beta.-difluoro-.alpha.-(trifluoromethyl)styrenes by palladium-catalyzed coupling of aryl iodides with pentafluoropropen-2-ylzinc reagent
摘要:
Substituted aromatic iodides are functionalized by pentafluoropropen-2-ylzinc, CF3C(ZnX)=CF2 (X = Br, I, or CF2=CCF3-), in the presence of Pd(PPh3)4 to give the corresponding arenes in good yields. This is particularly attractive for preparation of title styrenes substituted with groups such as -NO2 or CO2R, which are incompatible with organomagnesium reagents. The best yields of the title styrenes with electron-donating substituents were obtained in DMF. For electron-withdrawing substituents, the best results were achieved in triglyme. A correlation was observed between Hammett sigma constants and F-19 NMR chemical shifts (R = 0.93-0.99, n = 8) and 2J(F-F) coupling constants (R = 0.94, n = 8).
The transformation of the CF3 group into an olefinic CF2 group was achieved at nanoscopic aluminum chlorofluoride (ACF) with silane. Consecutive hydrogermylation and C−F activation steps enabled the transformation of an olefinic C−F into a C−H bond.
A niobium doped high surface aluminium fluoride (HS-AlF3) catalyst was prepared, using an approach in which niobium doped aluminium hydroxide fluoride obtained via reaction of aqueous HF with the respective metal alkoxides in isopropanol is further fluorinated under flow of CHClF2 at 200 °C. A comparable procedure was used to synthesize a Nb-free variant for comparison. Both catalysts exhibit very
[EN] PREPARATION OF HALOGEN AND HYDROGEN CONTAINING ALKENES OVER METAL FLUORIDE CATALYSTS<br/>[FR] PRÉPARATION D'ALCÈNES CONTENANT DE L'HYDROGÈNE ET UN HALOGÈNE SUR DES CATALYSEURS DE FLUORURE MÉTALLIQUE
申请人:SOLVAY FLUOR GMBH
公开号:WO2009010472A1
公开(公告)日:2009-01-22
Halogenated alkenes, especially fluorinated alkenes can be prepared from halogenated and fluorinated alkanes, respectively, by dehydrohalogenation or dehydrofluorination in the presence of a high-surface metal fluoride or oxifluoride. Preferably, trifluoroethylene, pentafluoropropene, tetrafluorobutenes or trifluorobutadiene are prepared. Aluminium fluoride is highly suitable. The metal fluoride or oxifluoride can be applied supported on a carrier.
An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis‐Superacid for the Dehydrofluorination of Fluoroalkanes
作者:Minh Bui、Kurt F. Hoffmann、Thomas Braun、Sebastian Riedel、Christian Heinekamp、Kerstin Scheurell、Gudrun Scholz、Tomasz M. Stawski、Franziska Emmerling
DOI:10.1002/cctc.202300350
日期:——
A pentafluoroorthotellurate doped aluminium chlorofluoride (ACF-teflate, AlCl0.1F2.8(OTeF5)0.1) was synthesized. The amorphous Lewis-superacidic material catalyzes the dehydrofluorination of fluoroalkanes to yield olefins and H2.
合成了五氟邻苯二甲酸根掺杂的氯氟化铝(ACF-teflate,AlCl 0.1 F 2.8 (OTeF 5 ) 0.1 )。无定形路易斯-超酸性物质催化氟代烷烃的脱氟化氢以产生烯烃和H 2。
Condensation of perfluoroisobutylene with compounds containing dihalomethylene groups