| abstract |
A method for stereoselective chemical synthesis, includes the steps of: (A) reacting a nucleophile and a chiral or prochiral cyclic substrate, said substrate comprising a carbocycle or a heterocycle having a reactive center susceptible to nucleophilic attack by the nucleophile, in the presence of a chiral non-racemic catalyst to produce a product mixture comprising a stereoisomerically enriched product wherein the product mixture further comprises a catalyst residue, at least a portion of the catalyst residue is in a first oxidation state, and the catalyst residue in the first oxidation state is active in catalyzing degradation of the stereoisomerically enriched product, and (B) chemically or electrochemically changing the oxidation state of the catalyst residue form the first oxidation state to a second oxidation state, wherein catalyst residue in the second oxidation state is less active in catalyzing degradation of the stereoisomerically enriched product than is catalyst residue in the first oxidation state. The method reduces erosion of the chiral purity of the stereoisomerically enriched product and reduces the chemical transformation to side products of the stereoisomerically enriched product and co-product(s). The deactivated catalyst is recoverable and recyclable. |