Formaldehyde → (2R,3S,4S,5R,6S)-3,4,5-tribenzyloxy-6-[4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl]-2-(hydroxymethyl)-6-methoxy-tetrahydropyran-2-carbaldehyde

Participants

Reaction Steps

To a solution of (2S,3S,4S,5R,6S)-3,4,5-tribenzyloxy-6-[4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl]-6-methoxy-tetrahydropyran-2-carbaldehyde 1h (0.82 g, 1.16 mmol, obtained from the synthetic method described in step 7 of example 1) in N,N-dimethylformamide (20 mL) were added 1,8-diazabicyclo[5.4.0]undec-7-ene (0.02 mL, 0.12 mmol) and formaldehyde (1.7 mL, 23.2 mmol, 37% in water) in turn. The mixture was stirred at room temperature for 5 hours and quenched with 10 mL of saturated aqueous sodium bicarbonate. The resulting mixture was filtered. The filtrate was extracted with ethyl acetate (20 mL×1 and 10 mL×3). The combined organic layers were washed with water (10 mL×3) and then saturated aqueous sodium chloride (10 mL×3), dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by silica gel chromatography eluted with PE/EtOAc(v/v)=5/1 to give the title compound 8a as yellow oil (0.56 g, 65.1%). The compound was characterized by the following spectroscopic data: 1H NMR (400 MHz, DMSO-d6) δ(ppm): 9.99 (s, 1H), 7.55-7.49 (m, 2H), 7.43 (d, 1H), 7.34-7.24 (m, 13H), 7.07 (dd, 2H), 6.95 (d, 2H), 6.72 (d, 2H), 5.38 (dd, 1H), 4.84 (m, 3H), 4.72 (d, 1H), 4.56-4.43 (m, 2H), 4.16 (d, 1H), 4.01 (d, 1H), 3.92 (q, 2H), 3.81 (m, 3H), 3.57 (dd, 1H), 3.25 (d, 1H), 2.70 (s, 3H), 1.27 (t, 3H).

Provenance & Evidence