Triethylamine → (2R,3S,4S,5R,6S)-2-(Acetoxymethyl)-6-(4-methoxyphenoxy)tetrahydro-2H-pyran-3,4,5-triyl triacetate

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Reaction Steps

p-methoxyphenol (20.5 mmol, 2.5 g) and trimethylsilyl trifluoromethanesulfonate (0.25 mL) were added to a solution of β-D-galactose pentaacetate (5.0 g, 12.8 mmol) in anhydrous CH2Cl2 at 0° C. under nitrogen. After 4 hours at 0° C., the reaction mixture was neutralized by addition of triethylamine (1 mL) and concentrated under reduced pressure. Purification by chromatography on silica gel (ethyl acetate-petroleum ether, v/v 1:3→1.5:1) afforded 6 as an amorphous white solid in 92% yield (5.35 g). Litt22 [αD]=+9.6° (c 0.54, CHCl3); [αD]23=+3° (c 1, CHCl3); 1H NMR (500 MHz, CDCl3): δ2.01, 2.06, 2.08 and 2.19 (4 s, 3H each, 4 OAc), 3.78 (s, 3H, OMe), 4.01 (m, 1H, H-5), 4.16 (dd, 1H, J5,6b 6.5 Hz, J6a,6b 11.3 Hz, H-6b), 4.23 (dd, 1H, J5,6a 6.9 Hz, H-6a), 4.92 (d, 1H, J1,2 8.0 Hz, H-1), 5.09 (dd, 1H, J2,3 10.4 Hz, J3,4 3.3 Hz, H-3), 5.5.44-5.48 (m, 2H, H-2 and H-4), 6.80 and 6.96 (2 d, 2H each, Ph).

Provenance & Evidence