摘要 |
<p>2,5-Disubstituted oxazolidin-4-one-3-ylacetyl chlorides and 1,2,5-substituted imidazolidin-4-one-3-yl-acetyl chlorides function as chiral auxiliary moieties in the asymmetric cycloaddition with aldimines to provide cis-azetidinones. The azetidinones are useful intermediates in the preparation of antibiotics.</p> |