Chiral ion pairs in catalysis: lithium salts of chiral metallocomplex anions as catalysts for asymmetric C-C bond formation

摘要

A series of Co(III) anionic complexes of Schiff bases obtained from substituted salicylaldehydes and optically active amino acids has been synthesized. The ion pairing of these anions to a lithium cation can be used to induce asymmetry into lithium-catalyzed trimethylsilylcyanation of aldehydes and Michael reactions. The influence of the temperature. solvent polarity and structural modification of the chiral anion on the enantioselectivity of the catalysis has been investigated.