Highly Stereoselective Intramolecular SN2 Cyclization Yielding Chiral Oxazolidin-2-ones: General Route to a-Hydroxy-(beta)-amino Acids

Intramolecular nucleophilic attack onto allylsulfonates promoted by silica gel acting as an acid catalyst provides expedient stereoselective access to 4.5-difunctionalized oxazolidin-2-ones. Precursors were prepared efficiently from enantiopure (alpha)-amino acids and subsequent manipulation of the oxazolidin-2-ones yielded enantiopure (alpha)-hydroxy-(beta)-amino acids.