A Novel Regio- and Stereospecific Hydrohalogenation Reaction of 2-Propynoic Acid and Its Derivatives

Article abstract of DOI:10.1021/jo00028a055

2-Propynoic acid and its derivatives are hydrohalogenated regio- and stereospecifically by reaction with lithium halides in acetic acid, or preferably with 1 equiv of acetic acid in refluxing CH3CN, to afford the thermodynamically unfavorable (Z)-3-halopropenoic acids and their derivatives as sole products.A rationale for the regio- and stereospecifity is briefly discussed.