Efficient one-step synthesis of chiral bidentate oxazoline-alcohol ligands via a cyclic imidate ester rearrangement

Various chiral bidentate oxazoline-alcohol ligands were obtained in a straightforward one-step synthesis via a cyclic imidate ester rearrangement. These chiral ligands were tested and compared in asymmetric diethylzinc additions to aldehydes resulting in selectivities of up to 87% ee. An interesting chirality switch was observed when a CPh2-tether instead of a CH2 was present, offering the opportunity for dual stereocontrol. (C) 2009 Elsevier Ltd. All rights reserved.