ABSTRACT
Chiral auxiliaries, n-methylephedrine, 3, and L-tartaric acids 4, were grafted to Merrifield resin 1 and aminomethylated Merrifield's resin 2, respectively, to afford polymeric ligands 3A and 4A. These polymer-supported ligands were used as auxiliaries in the catalytic asymmetric addition of diethylzinc to various aromatic aldehydes. In the heterogeneous reactions, the products with highest ee of 97% were obtained using 4A, while low ee was seen when 3A was used. Considering the enantioselectivity and reusability, the best results were obtained with 4A. After recycling of the polymer-supported tartaric acid, the catalytic reaction resulted in an ee of 96%. Thus, a new polymer-bound catalytic system has been developed for C-C bond forming reaction.
