(1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3-[[4-(trifluoromethoxy) phenyl]methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octane-1-carbaldehyde → 1-[(1R,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3-[[4-(trifluoromethoxy) phenyl]methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octan-1-yl]ethanol

Participants

Reaction Steps

To a solution of (1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3-[[4-(trifluoromethoxy) phenyl]methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octane-1-carbaldehyde 15p (0.71 g, 0.95 mmol) in dry tetrahydrofuran (15 mL) was added dropwise methylmagnesium bromide (0.64 mL, 1.91 mmol, 3M in tetrahydrofuran) under N2 at 0° C. After the addition, the mixture was warmed up to room temperature and stirred for 3 hours. The reaction mixture was quenched with saturated aqueous ammonium chloride (3 mL). To the mixture was added 20 mL of saturated aqueous sodium chloride and the resulting mixture was partitioned. The aqueous layer was extracted with ethyl acetate (20 mL×2). The combined organic layers were washed with saturated aqueous sodium chloride (30 mL×2), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo and the residue was purified by silica gel chromatography eluted with PE/EtOAc(v/v)=15/1 to give the title compound 15q as colourless oil (104 mg, 14.3%). The compound was characterized by the following spectroscopic data: 1H NMR (400 MHz, CDCl3) δ(ppm): 7.45 (s, 1H), 7.40 (s, 2H), 7.38-7.29 (m, 9H), 7.25-7.14 (m, 6H), 7.06 (d, 2H), 6.92 (d, 2H), 4.97 (dd, 2H), 4.81 (d, 2H), 4.29 (d 2H), 4.13-4.07 (m, 3H), 4.06 (s, 3H), 3.84 (d 1H), 3.69 (d, 1H), 3.58 (s, 1H), 1.21 (d, 3H).

Provenance & Evidence