Five chiral 1,4-bis(oxazoline) ligands, each bearing a bicyclic backbone, were prepared and examined in Mg(OTf)(2)-, Zn(OTf)(2)-, and Cu(OTf)(2)-catalyzed Diels-Alder reactions. The cycloadditions were carried out at room temperature and afforded enantiomeric excess up to 88%. Surprisingly, a non-C-2-symmetric bis(oxazoline) bearing a meso backbone was among the more efficient ligands examined. (C) 1997 Elsevier Science Ltd.
Five chiral 1,4-bis(oxazoline) ligands, each bearing a bicyclic backbone, were prepared and examined in Mg(OTf)(2)-, Zn(OTf)(2)-, and Cu(OTf)(2)-catalyzed Diels-Alder reactions. The cycloadditions were carried out at room temperature and afforded enantiomeric excess up to 88%. Surprisingly, a non-C-2-symmetric bis(oxazoline) bearing a meso backbone was among the more efficient ligands examined. (C) 1997 Elsevier Science Ltd.