Synthesis of 2-oxazolidinones from beta-lactams: stereospecific total synthesis of (-)-cytoxazone and all of its stereoisomers.

The synthetic correlation between two different antibiotic frameworks, the beta-lactams and 2-oxazolidinones, is described for the first time. In this approach, 2-oxazolidinones are prepared in stereomerically pure form from 3-hydroxy beta-lactams by a ring-opening-cyclization isomerization process. Application of this methodology to the total synthesis of the cytokine modulator, (-)-cytoxazone, and its three stereoisomers is demonstrated. [reaction: see text].