A novel reaction of β,β′-dihydroxy acids or esters with vanadium(V) trichloride oxide. New entry to the stereoselective synthesis of α-fluoro-α,β-unsaturated acids and esters

Abstract

β,β′-Dihydroxy carboxylic acids and esters, readily prepared from dibromofluoroacetate and aldehydes, underwent deoxygenation, followed by elimination of aldehyde by the action of vanadium(V) trichloride oxide at the reflux temperature of chlorobenzene for 1 h to afford the Z isomers of α-fluoro-α,β-unsaturated acids and esters, respectively, in fair to good yields. This reaction provides a new alternative entry to the stereoselective synthesis of such fluoro compounds.