Synthesis and catalytic activity of 10-(aminomethyl)isoborneol-based catalysts:: the role of the C(2)-group on the asymmetric induction

Five enantiopure C(2)-substituted 10-[(dimethylamino)methyl]isoborneols has been prepared by a novel straightforward camphor-based route, and probed as delta-amino-alcohol ligands for the enantioselective addition of diethylzine to benzaldehyde. The established route constitutes a divergent model procedure for this class of delta-amino-isoborneol ligands, allowing different substitutions, not only at the nitrogen atom, but also at the more interesting hydroxyl-bearing C(2)-norbornane position. This last synthetic possibility has made possible a study of the role played by the group located at the C(2)-norbornane position on the catalytic activity. New catalyst models and transition-state models for explaining such a role are also proposed and discussed. (C) 2003 Elsevier Ltd. All rights reserved.