Asymmetric Reaction of Simple Nitro Compounds with Chiral 1,3-Oxazolidin-2-ones.

The chiral oxazolidinone 1 (=[(3aS,6R,7aR)-tetrahydro-8,8-dimethyl-2-oxo-4H-3a,6-methano-1,3-benzoxazol-3-yl](oxo)acetaldehyde) was found to react stereoselectively with simple nitro compounds in the presence of Al2O3 or Bu4NF⋅3 H2O (TBAF) as catalysts, affording the diastereoisomeric nitro alcohols 3–6 with good asymmetric induction. When Al2O3 was used, the (S)-configuration at the center bearing the OH group was generated, with the relative syn-configuration for the major diastereoisomers. In the case of the nitro-aldol reaction catalyzed by TBAF, an opposite asymmetric induction was found for two nitro compounds. In contrast to 1, compound 12 (=((4R,5S)-4-methyl-2-oxo-5-phenyl-1,3-oxazolidin-3-yl)(oxo)acetaldehyde), a derivative of Evans auxiliary, gave rise to poor asymmetric induction in Henry reactions.