Axially Chiral N-(o-aryl)-4-Hydroxy-2-oxazolidinone Derivatives from Diastereoselective Reduction of N-(o-aryl)-2,4-oxazolidinediones: Thermally Interconvertible Atropisomers via Ring-Chain-Ring Tautomerization

作者：Demir Ordu Oeznur; Dogan Ilknur^*

来源：Chirality, 2010, 22(7): 641-654.

DOI：10.1002/chir.20811

• axial chirality
• diastereoselective reduction
• ring-chain-ring tautomerization
• enantioselective HPLC
• enantiomer separation
• barrier to enantiomerization
• 2,4-oxazolidinediones
• temperature-dependent NMR

The reduction of the axially chiral N-(o-aryl)-5,5-dimethyl-2,4-oxazolidinediones by NaBH(4) yielded axially chiral N-(o-aryl)-4-hydroxy-5,5-dimethyl-2-oxazolidinone enantiomers having a chiral center at C-4, with 100% diastereoselectivity as has been shown by their (1)H and (13)C NMR spectra and by enantioselective HPLC analysis. The resolved enantiomeric isomers were found to interconvert thermally through an aldehyde intermediate formed upon ring cleavage via a latent ring-chain-ring tautomerization. It was found that the rate of enantiomerization depended on the size and the electronic effect of the ortho substituent present on the aryl ring bonded to the nitrogen of the heterocycle. Chirality 22: 641-654, 2010.

• 出版日期2010-7