| Abstract
| - A practical synthesis of methyl (2R,3S)-3-(4-methoxyphenyl)glycidate (−)-2, a key intermediate for diltiazem (1), was developed. Treatment of methyl (E)-4-methoxycinnamate 3 with chiral dioxirane, generated fromchiral ketone 4, provided (−)-2 in 77% ee and 89% yield. Thecrude mixture of (−)-2 and 4 was efficiently separated bythe use of novel and simple equipment performing a lipase-catalyzed transesterification and a continuous dissolutionand crystallization to furnish the optically pure (−)-2 andrecovery of 4 in 74% and 91% yield, respectively.
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