EXTREMELY POWERFUL CHIRAL 2-OXAZOLIDINONE AUXILIARIES

Both enantiomers of cis-4,5-disubstituted 2-oxazolidinones, DHAOx, DMAOx, CPAOx and HMCOx, which are sterically congested and conformationally fixed by bicyclo[2.2.1] and [2.2.2] ring systems are newly prepared by the Diels-Alder reactions of 2-oxazolone with the cyclic dienes such as anthracenes and cyclopentadienes followed by optical resolution with MAC acid. These compounds, particularly DMAOx and HMCOx, serve well as the most powerful 2-oxazolidinones chiral auxiliaries reported so far for the asymmetric reactions such as alkylations, the Diels-Alder reactions, the Michael-type additions and aldol reactions. Sterically congested 2-aminoalcohol derivatives derived from the ring-opening of DHAOx and DMAOx are shown to be highly useful auxiliaries for enantioselective additions of diethylzinc to aldehydes and enantiodivergence of meso-dicarboxylic anhydrides.