This study presents an efficient procedure for synthesis of 3,4,5-trisubstituted 3H-oxazol-2-ones and 3,4-disubstituted (Z)-oxazolidin-2-ones from substituted propargyl alcohols and aryl/alkyl isocyanates in the presence of LiOtBu, a base, and DMF, a solvent. This one-step, low-cost and gram scale synthesis exhibits superior atom economy, good to excellent yields, enhanced substrate scope and, high functional group tolerance and uses column chromatography-free purifications. Further, a product containing bromo substituent was successfully examined for Suzuki coupling with a view to amplifying the complexity of the molecule. Finally, the three component (aniline, Di-tert-butyldicarbonate and propargyl alcohol) reaction was demonstrated to get the oxazolon-2-ones (3H-oxazol-2-one and oxazolidin-2-one). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim