Synthesis of 2-Oxazolidinones from β-Lactams: Stereospecific Total Synthesis of (−)-Cytoxazone and All of Its Stereoisomers

The synthetic correlation between two different antibiotic frameworks, the β-lactams and 2-oxazolidinones, is described for the first time. In this approach, 2-oxazolidinones are prepared in stereomerically pure form from 3-hydroxy β-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.