The major patents concerning chirally modified nickel catalysts by enantiomerically pure tartaric acid are comprehensively surveyed. The methods of catalyst's preparation for attaining a high enantioselectivity and the synthetic routes for obtaining optically active compounds by using these tartaric acid-modified nickel catalysts are summarized. A recently claimed patent dealing with the robust chiral nickel catalyst, which exhibits an exceptionally high stability after preparation is also introduced.

Asymmetric synthesis, chiral catalysts, chiral compounds, enantio-differentiating hydrogenation, methyl acetoacetate, modified nickel catalyst, nickel powder, Raney nickel, tartaric acid.

Graduate School of Science and Engineering for Research, University of Toyama, Gofuku, Toyama 930- 8555, Japan.