Reversal of enantioselection in an aldol reaction catalyzed by sterically congested bis(oxazoline)–Cu(II) complexes
摘要:
The use of sterically congested C-2-symmetrical bis(oxazoline) ligands with methylene and ethylene spacers between the oxazoline rings results in the reversal of the enantioselection for aldol reactions catalyzed by bis(oxazoline)-Cu(II) complexes. (C) 1999 Elsevier Science Ltd. All rights reserved.
Sterically constrained and highly congested N-acetyl-DMAOx (1a) serves well as a useful chiral acetyl enolate equivalent which permits a diastereoselective and direct approach to 'acetate' aldols (2) including statine derivative.