Fluorination with caesium fluoroxysulphate. Room temperuture flourination of phenyl substituted olefins

Abstract

Room-temperature fluorination of 1,1-diphenylethene with caesium fluoroxysulphate in methylene chloride resulted in an addition elimination process, thus yielding 1, 1-diphenyl-2-fluoroethene, while in the presence of nucleophile containing species, i.e., hydrogen fluoride, methanol, or acetic acid, either vicinal difluorides, methoxy fluorides or acetoxy fluorides were formed. Reaction with norbornene in the absence of a nucleophile gave only 7-fluoronortricyclane and 7-syn-fluoronorborn-2-ene, while similar reaction with 2-phenylprop-1-ene gave 3-fluoro and 3,3-difluoro-2-phenylprop-1-ene. 1,1-diphenylprop-1-ene, 1,1-diphenyl-2-fluoroethene and 1,1-diphenyl-2-bromoethene were converted with caesium fluoroxysulphate in the presence of various nucleophile donating species, i.e. hydrogen fluoride, methanol, or acetic acid, to adducts with nucleophile bonding following Markovnikov type regioselectlvity.