Convenient and expedient routes have been described, which allows the regio-, chemo- and stereoselective preparation of 4,5-disubstituted oxazolidin-2-ones 2 and oxazolidin-2-thiones 3, based on the reaction of the α-epoxyketones 1 with urea, thiourea or sodium thiocyanate as promising starting materials, in the presence of a catalytic amount of p-toluenesulphunic acid (PTSA).
