0.21 g (0.92 mmol) of (R)-3-(naphth-2-yloxymethyl)-pyrrolidine is dissolved in 3.80 ml of dichloromethane and then 0.31 g (1.01 mmol) of 3-carbamoylisoxazol-5-ylmethyl 4-nitrophenyl carbonate and 0.15 ml (1.38 mmol) of N-methylmorpholine are added. The mixture is stirred at ambient temperature for 20 hours and then water is added to the reaction medium. After extraction of the aqueous phase with dichloromethane, the organic phases are successively washed three times with a 1M aqueous sodium hydroxide solution and then twice with a saturated aqueous ammonium chloride solution. After having dried the organic phases over sodium sulphate, they are filtered and the filtrate is evaporated to dryness. 0.14 g of the desired product is thus obtained in the form of a white solid after purification on a column of silica gel, elution being carried out with a dichloromethane/methanol mixture, and then taken up in isopropyl ether.
