Efficient Asymmetric Synthesis of Chiral Hydroxy-γ-butyrolactones
作者:Iwan R. Davies、Matt Cheeseman、Rachel Green、Mary F. Mahon、Andrew Merritt、Steven D. Bull
DOI:10.1021/ol9008365
日期:2009.7.2
Treatment of β-vinyl-β-hydroxy-N-acyloxazolidin-2-ones with VO(acac)2 and tert-butyl hydroperoxide results in formation of unstable epoxides that are ring-opened by intramolecular nucleophilic attack of their exocyclic carbonyl fragments to afford highly functionalized trisubstituted hydroxy-γ-butyrolactones in >95% de, with a polymer-supported oxazolidin-2-one having been used to transfer this methodology
A Temporary Stereocentre Approach for the Stereodivergent Synthesis of Either Enantiomer of α-Methyloctanal
作者:D. Gangani Niyadurupola、Iwan R. Davies、Richard Wisedale、Steven D. Bull
DOI:10.1002/ejoc.200700782
日期:2007.11
The aldol reaction of a chiral N-(acyl)oxazolidin-2-one with 2-methyleneoctanal or (E)-2-methyloct-2-enal affords chiral aldol products whose alkene functionalities were hydrogenated using Brown's or Wilkinson's catalyst to afford syn- or anti-selective products with excellent levels of diastereocontrol. Subsequent retro-aldol cleavage of these syn- or anti-adducts resulted in the formation of either