Dichloromethane → 5-{[(S)-1-(4-Chloro-phenyl)-ethyl]-methoxycarbonyl-amino}-3-hydroxy-3-phenyl-pentanoic acid methyl ester

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Reaction Conditions

Reaction Steps

Et2Zn (1 M in hexane, 55 mL) was added dropwise to [(S)-1-(4-chloro-phenyl)-ethyl]-(3-oxo-3-phenyl-propyl)-carbamic acid methyl ester (3.80 g) dissolved in 1,2-dichloroethane (30 mL) and chilled to 0° C. under argon atmosphere. Then, (Ph3P)3RhCl (0.50 g) was added followed by the dropwise addition of methyl bromoacetate (1.0 mL) dissolved in 1,2-dichloroethane (10 mL). The resulting solution was stirred at 0-5° C. for 1 h and at ambient temperature for another 1.5 h. The solution was poured into ice-cold half-saturated aqueous NH4Cl solution (150 mL). After addition of dichloromethane, the mixture was filtered through Celite and was extracted with an additional portion of dichloromethane. The organic phase was separated and washed with water and dried (MgSO4). The solvent was removed and the residue was purified by chromatography on silica gel (cyclohexane/ethyl acetate 85:15->70:30) to give the title compound as a mixture of two diastereomers.

Provenance & Evidence