An efficient and high-yield procedure to prepare methyl N-benzoylamino-3-arylacrylates from unsaturated (Z)-2-aryl-4-arylidene-5-(4H)-oxazolones and Hg(OAc) 2 in methanol is described herein. The observed reactivity of mercury(II) acetate here is different to its usual metallating behaviour, since it cleaves the unsaturated oxazolone ring without change of stereochemistry.