146803-41-0

161529-13-1

146803-41-0

To an anhydrous dichloromethane (10 mL) solution of oxalyl chloride (1.89 g, 15.0 mmol) was added anhydrous dichloromethane (10 mL) solution of dimethyl sulfoxide (1.2 g, 15.0 mmol) dropwise at -65 °C. After stirring for 30 minutes, anhydrous dichloromethane (20 mL) solution of N-fluorenylmethoxycarbonyl-L-alaninol (3.0 g, 10.0 mmol) was added slowly dropwise. After continued stirring for 2 h, triethylamine (3.0 g, 30 mmol) was added dropwise, followed by gradual warming of the reaction mixture to room temperature. Upon completion of the reaction, the reaction was quenched with water and extracted with dichloromethane (3 x 100 mL). The organic phases were combined, washed with saturated brine and dried over anhydrous sodium sulfate. After filtration, the solvent was removed by concentration under reduced pressure to give the white solid product methyl (S)-(9H-fluoren-9-yl)methyl(1-oxopropan-2-yl)carbamate (2.8 g, 94.9% yield).