Methanesulfonic Acid → (2S,3R,4S,5S,6R)-2-[4-chloro-3-[[4-(2,2,2-trifluoroethoxy)phenyl]methyl]phenyl]-6-(hydroxymethyl)-2-methoxy-tetrahydropyran-3,4,5-triol

Participants

Reaction Conditions

Reaction Steps

4-bromo-1-chloro-2-[[4-(2,2,2-trifluoroethoxy)phenyl]methyl]benzene 7d (6.15 g, 16.2 mmol) was dissolved in 150 mL of mixed solution (THF and n-hexane, v:v=2:3) and cooled to −78° C., followed by dropwise addition of a solution of nBuLi in n-hexane (10 mL, 24.3 mmol). The reaction was stirred for 1 hour at −78° C. before a solution (35 mL) of (3R,4S,5R,6R)-3,4,5-tris(trimethylsilyloxy)-6-(trimethylsilyl-oxymethyl)tetrahydropyran-2-one 2f (8.32 g, 17.8 mmol) in n-hexane was dropwise added. Then, the reaction mixture was stirred for 2 hours at −78° C. before 50 mL methanol and 3.2 mL methylsulfonic acid were added. The reaction mixture was warmed and stirred for 16 hours at room temperature. Thereafter, the reaction mixture was concentrated under reduced pressure and was partitioned after 30 mL saturated sodium bicarbonate solution and 10 mL water were added. The aqueous phase was extracted with ethyl acetate (100 mL×3) and the organic extract was washed with saturated sodium chloride solution (20 mL) and combined, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica gel chromatography with elution system D to obtain the title compound (2S,3R,4S,5S,6R)-2-[4-chloro-3-[[4-(2,2,2-trifluoroethoxy)phenyl]methyl]phenyl]-6-(hydroxymethyl)-2-methoxy-tetrahydropyran-3,4,5-triol 7e (3.93 g, white solid), yield: 49.2%. 1H NMR (400 MHz, CD3OD): δ 7.57 (d, 1H), 7.49 (dd, 1H), 7.38 (d, 1H), 7.18 (d, 2H), 6.99-6.88 (m, 2H), 4.49 (q, 2H), 4.19-4.01 (m, 3H), 3.99-3.91 (m, 1H), 3.89-3.71 (m, 2H), 3.66-3.55 (m, 1H), 3.49-3.39 (m, 1H), 3.14-3.04 (s, 3H).

Provenance & Evidence