Add acetyl chloride (0.13 mL, 1.82 mmol) to an ice cold solution of (2R,5R)-5-[2-amino-3-(3-benzyloxyphenyl)-1-hydroxypropyl]-2-(1-methylcyclopentylmethoxy)-morpholine-4-carboxylic acid tert-butyl ester (0.91 g, 1.652 mmol) and N,N-diisopropyl-ethylamine (0.58 mL, 3.30 mmol) in dichloromethane (20 mL). Stir 15 minutes and dilute with ethyl acetate and wash with 1 N hydrochloric acid, saturated aqueous sodium chloride, dry (magnesium sulfate) and purify (silica gel chromatography, elutin with dichloromethane/ethyl acetate) to give the desired compound (246 mg).
