Copper(I)-catalyzed solvolysis of gem-chlorofluoro- and gem-bromofluorocyclopropanes. Preparation of 2-fluoroallylic ethers, esters and alcohols
作者:Maxim A. Novikov、Nikolai V. Volchkov、Maria B. Lipkind、Oleg M. Nefedov
DOI:10.1016/j.jfluchem.2015.09.001
日期:2015.12
Copper(I)-catalyzed solvolysis of gem-chlorofluoro- and gem-bromofluorocyclopropanes in MeOH, NaOAc/AcOH, NaOAc/DMF, HCO2Na/HCO2H or water/dioxane affords 2-fluoroallylic ethers, esters or alcohols in moderate to excellent yields. The reaction pathway involves isomerization of gem-fluorohalocyclopropanes to 2-fluoroallylic halides followed by nucleophilic substitution of a halide onto an O-nucleophile
diphenyliodonium triflate in the presence of CuCl. The salt 4 then undergoes Michael addition followed by Wittig olefination to give the corresponding monofluoroethylene compounds in good yields. The reaction of 4 with the caesium salts of salicylaldehyde derivatives in DMF at 130 °C affords the corresponding monofluorinated chromenes in a one-pot synthesis. The hydrolysis of 4 in the presence of sodium hydroxide