Patent ID: 7169793

Claim:
A process for separating optical isomers, comprising: a) providing in an organic solvent a mixture of optical isomers of a sulfoxide group-containing compound of the structure: wherein R′ is where R 1 , R 2 , R 3 , and R 4 are each independently hydrogen, alkyl, alkoxy, halogen, halogenated alkoxy, alkylcarbonyl, alkoxycarbonyl, oxazolyl, or trifluoroalkyl; R 5 , R 6 , and R 7 are each independently hydrogen, alkyl, halogenated alkyl, alkylthio, halogenated alkylthio, alkoxy, halogenated alkoxy, alkoxyalkoxy, dialkylamino, piperdino, morpholino, halogen, phenylalkyl or phenylalkoxy; R 8 is hydrogen or lower alkyl; R 9 and R 10 are each independently hydrogen, halogen, alkyl or alkoxy; or a salt thereof, said optical isomers having R and S configurations at the sulfur atom of the sulfoxide group; b) reacting the mixture of optical isomers with i) a coordinating agent containing a transition metal, and ii) a chelating agent, to form transition metal complexes at the sulfoxide group; c) reacting transition metal complexes with an organic acid, or a salt thereof, to form an addition product, wherein at least one of said chelating agent and said organic acid contains a chiral center and is in a substantially enantiomerically pure form, each of said transition metal complexes of said optical isomers forming an adduct with said organic acid or a salt thereof and the different adducts having at least one physical property in which they differ from one another; d) separating one adduct from another adduct based on said at least one physical property; and e) treating a separated adduct with an acid or base to decompose said transition metal complex at said sulfoxide group, to recover an optical isomer of the sulfoxide group-containing compound.