Asymmetric Synthesis of Proline Derivatives from (2R) and (2S)-2-tert-Butyl-3-Benzoyl-4-Methyleneoxazolidin-5-one

Article abstract of DOI:10.1016/0040-4020(95)98711-P

The conjugate addition of enamines (2a,b) to the chiral oxazolidinones (1) or ent-(1) favours cis 2,4-substituted oxazolidinone adducts while trans 2,4-substituted oxazolidinone adducts are favoured from the addition 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 overall yield.The extenstion of this protocol to the synthesis of perhydroindole carboxylic acid suffered from poor overall stereochemical control.