Stereoselective hydroxycarbonylation of vinyl bromides to alpha,beta-unsaturated carboxylic acids in the ionic liquid [BMIM]PF6.

(E/Z)-isomers containing vinyl bromides were stereoselectively carbonylated to the corresponding (E)-alpha,beta-ethylenic carboxylic acids in the ionic liquid [BMIM]PF6. Vinyl dibromides also underwent hydroxycarbonylation to give monoacids. The products are pure by proton NMR spectroscopic determination without purification by silica gel column chromatography or recrystallization.