Optically Active Ketoiminato Co(II) Complexes for Enantioselective Borohydride Reduction

The ketoiminato cobalt(II) complexes 1 and 2 developed by Mukaiyama, Yamada and co-workers are utilized for catalytic asymmetric reductions. The asymmetric reduction using 1 and 2 can use sodium borohydride, a widely used reducing agent. Therefore, this method is receiving much attention as it is likely to become a popular, convenient and economical method for obtaining optically active alcohols, amines, 1,3-diols, 3-hydroxycarbonyl compounds, β-substituted amides and so forth.