| 摘要 |
PURPOSE: Provided is a method for preparing the optical isomers of 1,1'-bi-2-naphthol to improve the purity and the yield, wherein the optical isomers is used as a chiral ligand for the asymmetric catalytic reaction. CONSTITUTION: The method comprises the steps of condensing the racemic mixture of 1,1'-bi-2-naphthol represented by the formula 1 with 2,2'-dimethylcyclopropanecarboxylic acid represented by the formula 2 to obtain the mixture (the formula 3) of (S)-1,1'-bi-2-naphthol-mono-2,2'-dimethylcyclopropanecarboxylate and (R)-1,1'-bi-2-naphthol-mono-2,2'-dimethylcyclopropanecarboxylate; recrystallizing the mixture (the formula 3) to separate (S)-1,1'-bi-2-naphthol-mono-2,2'-dimethylcyclopropanecarboxylate and (R)-1,1'-bi-2-naphthol-mono-2,2'-dimethylcyclopropanecarboxylate; and hydrolyzing the separated two isomers to obtain (S)-1,1'-bi-2-naphthol-mono-2,2'-dimethylcyclopropanecarboxylic acid and (R)-1,1'-bi-2-naphthol-mono-2,2'-dimethylcyclopropanecarboxylic acid. Preferably 2,2'-dimethylcyclopropanecarboxylic acid of the formula 2 is (S)-2,2'-dimethylcyclopropanecarboxylic acid. The recrystallization is carried out by using n-hexane.
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