A reaction mixture containing tert-butyl (2S)-2-hydroxy-3-phenoxypropyl{[(2R)-6-iodo-3,4-dihydro-2H-chromen-2-yl]methyl}carbamate (Example 81, 8.625 mmol, 1.0 eq.), tert-butyldimethylsilyl chloride (10.35 mmol, 1.2 eq.), and imidazole (21.5625 mmol, 2.5 eq.) in anhydrous DMF (18 mL) was stirred at 27° C. overnight. The resulting mixture was then cooled to room temperature, poured into water, and extracted with diethyl ether. The organic extract was washed with water, brine, dried over anhydrous sodium sulfate, concentrated, and purified by medium pressure column chromatography (Biotage 40S normal phase silica gel column, hexanes:EtOAc=100:5). The product was obtained as a colorless oil in 97% yield. MH+=654.0, retention time (LC-MS)=5.29 min.
