HCID 117928482, compound → 1-[(1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3[(4-ethoxyphenyl)methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octane-1-yl]propan-1-ol

To a solution of (1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octane-1-carbaldehyde 1k (0.3 g, 0.43 mmol, obtained from the synthetic method described in step 10 of example 1) in anhydrous tetrahydrofuran (10 mL) was added dropwise ethylmagnesium bromide (1.7 mL, 1.7 mmol, 1M) at 0° C. The mixture was stirred at room temperature for 16 hours, quenched with 2 mL of saturated aqueous ammonium chloride, and extracted with dichloromethane (20 mL×2). The combined organic layers were washed with saturated aqueous sodium chloride (5 mL×2), dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by silica gel chromatography eluted with PE/EtOAc(v/v)=10/1 to give the title compound 3a as colorless oil (48 mg, 16.0%). The compound was characterized by the following spectroscopic data: 1H NMR (400 MHz, CDCl3) δ(ppm): 7.40 (m, 1H), 7.31 (m, 10H), 7.18 (m, 5H), 7.07 (m, 2H), 6.90 (m, 2H), 6.75 (m, 2H), 4.93 (m, 2H), 4.77 (m, 2H), 4.29 (d, 1H), 4.21 (d, 1H), 4.03 (m, 3H), 3.96 (m, 4H), 3.81 (m, 1H), 3.65 (m, 2H), 2.23 (d, 1H), 1.51 (m, 2H), 1.38 (t, 3H), 0.93 (t, 3H).