Stereoselective hydrohalogenation of alkynoic acids and their esters in ionic liquids

Abstract

A novel procedure is described for the hydrohalogenation of alkynoic acids and their esters using N-alkylpyridinium ionic liquids. Hydrohalogenating agents were prepared by mixing N-alkylpyridinium halides with an equimolar amount of trifluoroacetic acid. The corresponding halogenated alkenes were obtained in good yields with high diastereoselectivity.