| 摘要 |
A process of synthesizing enantiomerically pure compounds defined by Formula V, <IMAGE> (V) which are useful as chiral auxiliaries is disclosed. The process comprises, first, combining a base of Formula Y-Z+ (Formula I), wherein Y- is an organic anion and Z+ is an inorganic cation, with a compound of Formula II, <IMAGE> (II) wherein R1 is a C1-C4 alkyl group and R2 is the same as R1, or wherein R1 and R2 together form cyclopentane or cyclohexane, and wherein R3 is a substituted or unsubstituted aryl group, to form a compound defined by Formula III, <IMAGE> (III) then: (b) reacting the compound of Formula III with a cyclic epoxide defined by Formula IV, <IMAGE> (IV) wherein n is 1, 2, or 3, to form a racemic mixture of a compound defined by Formula V. <IMAGE> (V) In a preferred embodiment, the method further comprises stereospecifically esterifying one of the enantiomers of the racemic mixture of compound (V) and a carboxylic acid with an enzyme in an organic solvent, wherein said acid is a C2-C20 alkyl acid, benzoic acid or a C2-C14 alkyl benzoic acid, and then separating the esterified enantiomer from the non-esterified enantiomer.
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