Introduce 200 g of benzyl (2S,3aS,7aS)-octahydro-1H-indole-2-carboxylate and 1.5 liters of dichloromethane into a reactor, then bring the temperature of the reaction mixture to 0° C. and add 201 ml of diisopropylethylamine followed by 132 g of (2R)-2-bromo-propionyl chloride. Subsequently, bring the mixture to ambient temperature. After stirring for 1 hour at that temperature, wash the mixture with water and then with a dilute acetic acid solution. The benzyl (2S,3aS,7aS)-1-[(2R)-2-bromopropionyl]octahydro-1H-indole-2-carboxylate solution so obtained is used as it is in the following Step.
