Synthesis of a new chiral oxazolidinone auxiliary based on D-xylose and its application to the Staudinger reaction

The synthesis of a new chiral oxazolidinone auxiliary based on D-xylose is described which is employed in diastereoselective Staudinger-type beta-lact am syntheses. Using 2-chloro-1-methylpyridinium iodide as the dehydrating r eagent, the reaction of auxiliary tethered acetic acid with acyclic or cycl ic imines gave the desired beta-lactams in good yields with excellent cis- or trans-selectivity depending on the geometry of the imine. X-Ray structur e determination of one of the obtained compounds corroborated the absolute configuration for all cis products. (C) 2000 Elsevier Science Ltd, All righ ts reserved.