ASYMMETRIC-SYNTHESIS OF PROLINE DERIVATIVES FROM (2R) AND 2-TERT-BUTYL-3-BENZOYL-4-METHYLENEOXAZOLIDIN-5-ONE

The conjugate addition of enamines (2a,b) to the chiral oxazolidinones (1) or ent-(1) favours cis 2,4-substituted oxazolidinone adducts whil e trans 2,4-substituted oxazolidinone adducts are favoured from the ad dition reactions of enamine (2c). The diastereomeric adducts from the addition of (2a) to (1) are readily separated and can be converted to (5R, 2S) and (5S, 2R) 5-iso-propyl proline efficiently and in good ove rall yield. The extenstion of this protocol to the synthesis of perhyd roindole carboxylic acid suffered from poor overall stereochemical con trol.