Asymmetric synthesis of proline derivatives from (2R) and (2S)-2-tert-butyl-3-benzoyl-4-methyleneoxazolidin-5-one
摘要:
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.
Two free radical routes for the preparation of novel difluoromethylene-linked serine-O-glycopeptide analogues
作者:Timothée F. Herpin、William B. Motherwell、Jean-Marc Weibel
DOI:10.1039/a700928c
日期:——
The first examples of gem-difluoromethylene-linked analogues
of serine-derived glycopeptides have been prepared in a highly
stereoselective manner using two complementary free radical chain
reactions.