Abstract Ozonolysis of protected 3, 4-dehydro-DL-proline (2) in methanol gives as the initially isolable product, a seven-membered ring cyclic peroxide (5). Compound 5 undergoes rearrangement thermally to give methyl N-tosylglycinate (8) and a stereochemical mixture of oxazolidine aldehyde esters (7). Structural evidence for 7 came from detailed 13 C nmr studies of 7 and its reduction product (9).
![[2-(hydroxymethyl)-5-methoxy-3-(4-methylphenyl)sulfonyl-1,3-oxazolidin-2-yl]methanol Structure](https://image.chemsrc.com/caspic/490/63423-91-6.png)
