Chirality transfer bipyridine ligands

Reductions can also be performed in water. Systems for reduction of ketones in water can be water-compatible sodium and lithium borohydrides, amino acid-based cationic surfactants to reduce aryl ketones [19], iridium hydrides used in transfer hydrogenations, such as [Cp Irm(bpy)H]+ (Cp — q5-C5Mes, bpy = 2,2 - bipyridine) [20], and IrHCI2(cod) 2 with a chiral diaminodiphosphine ligand to form secondary alcohols in high enantioselectivity and almost quantitative yield (Equation 4.12) [21]. 

Bipyridine (bpy) diboronic acid 239 developed by Nakashima and its iron (II) (as FeC12) complex produce CD-active saccharide complexes. The CD activity of 239 was derived from the asymmetric immobilization of the two-pyridine units on saccharide binding. The copper(II) complex gave a CD band in the region of the metal to ligand charge transfer band. A or A complexes were found depending on the complexed saccharide. For example, the o-maltose complex adopted A chirality whereas the o-cellobiose complex adopted A chirality. 

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