Here we report a new catalytic asymmetric synthesis of oxazolidin-2-ones 4 and Cbz-protected 1,2-amino alcohols 5. Our sequence is based on the chemistry of previously unknown 5-acyloxy-oxazolidin-2-ones, which are obtained via proline-catalyzed direct asymmetric three-component Mannich reaction and Baeyer-Villiger oxidation.