Hydroxy acid complexes. I. Complexes containing optically active lactic acid and pantoic acid

Abstract

Complexes of the type [Co(en)2ha]Cl, where ha is the diacid anion of lactic or pantoic (2,4-dihydroxy-3,3-dimethylbutyric ) acid, were prepared by the reaction of optically active lactic acid with rac-[Co(en)2C03] + and optically active pantoyl lactone with trans-[Co(en)2Cl2]C104. Several optical isomers have been isolated from the reaction products by thin layer chromatography. These complexes have been characterized by nmr, electronic absorption, ORD, and CD spectra and their relative absolute configurations have been assigned. Data suggest that the hydroxy acid anions coordinate in a preferred conformation and configurational and vicinal contributions to the optical activity of these complexes are discussed.