Optical resolution of tris(pentane-2,4-dionate) complexes of transition-metal ions

Abstract

Optically pure Δ(–)[Cr(pd)₃] and partly resolved [Ru(pd)₃] with the Δ(+)isomer in excess are afforded by an asymmetric synthesis from the corresponding (+)-tartrate complex (pd = pentane-2,4-dionate). Complexes rac-[M(pd)₃](M = Co^III, Cr^III, Rh^III, or Ru^III) partition between diethyl (+)-tartrate and (–)-α-pinene with a partial resolution of the optical isomers, the Λ isomer being generally the more soluble in the ester layer. The optical isomers of [Rh(pd)₃] have been obtained from the racemic complex through the optically enriched fractions provided by the differential partitioning.