Asymmetric Catalysis of Carbon-Carbon Bond-Forming Reactions Using Metal(salen) Complexes

The use of metal(salen) complexes in the asymmetric syntheses of cyanohydrins and amino acids have been developed as important and reliable methods of obtaining these highly versatile chiral intermediates. Thus, we have developed a number of titanium and vanadium(salen) complexes, with ligands derived from (R,R)-cyclohexane-1,2-diamine, which catalyze the synthesis of enantiomerically enriched O-protected cyanohydrins from various carbonyl compounds and cyanide sources. Nickel, copper and cobalt(salen) complexes have also been developed, as catalysts for the preparation of non-racemic amino acids under phasetransfer conditions.