Practical Syntheses of N-Acetyl (E)-β-Arylenamides

A facile and practical method for the preparation of (E)--arylenamides [(E)-N-(1-arylprop-1-en-2-yl]acetamides] has been developed by reductive acetylation of the corresponding oximes with iron(II) acetate as the reducing reagent. Employment of hexamethylphosphoramide as the solvent was found to be critical for the high E/Z selectivity. The methodology has been applied in efficient syntheses of a key chiral intermediate of tamsulosin by asymmetric hydrogenation.