Fluoroacrylic acid esters

Abstract

Two synthetic routes to α-fluoroacrylates are described: Chlorofluorocarbene is generated from CHFCl 2 under phase- transfer catalysed conditions. In situ addition of this carbene to an enol ether gives a cyclopropane. Then this compound is transformed into α-fluoroacrolein. Photochemical bromination of this aldehyde gives an acid bromide. This intermediate can lead to various α-fluoroacrylic acid esters, particularly to the phenyl ester, which is of interest for aeronautic. The enol ether can be replaced by 1-ethoxy-l-phenoxy ethylene. Thermolysis of the carbene adduct leads directly to phenyl α-fluoroacrylate.