Regiospecific Hydration of γ-Hydroxy-α,β-acetylenic Esters: A Novel Asymmetric Synthesis of Tetronic Acids

[reaction: see text] The optically active gamma-hydroxy-alpha,beta-acetylenic esters are obtained from the enantioselective reaction of methyl propiolate with both aliphatic and aromatic aldehydes. These compounds can undergo regiospecific hydration in the presence of Zeise's dimer, [PtCl(2)(C(2)H(4))](2), to generate the optically active tetronic acids.