Methanesulfonic Acid → (2S,3R,4S,5S,6R)-2-(2-(allyloxymethyl)-4-chloro-5-(4-ethylbenzyl)phenyl)-6-(hydroxymethyl)-2-methoxytetrahydro-2H-pyran-3,4,5-triol

Participants

Reaction Steps

To a solution of 1-(allyloxymethyl)-2-bromo-5-chloro-4-(4-ethylbenzyl)benzene in dry THF:toluene (1:2, 2.4 mL) was added n-BuLi (0.3 mL, 2.5 M in hexane) dropwise under argon. After it was stirred for 1 h, a cooled solution (−70° C.) of (3R,4S,5R,6R)-3,4,5-tris(trimethylsilyloxy)-6-((trimethylsilyloxy)methyl)-tetrahydropyran-2-one in dry toluene (1.8 mL) was added dropwise to the reaction mixture. After being stirred for 3 h, the reaction was quenched by addition of ice water and extracted with EtOAc. The combined organic layers were washed 2× with water, 2× with brine, and then dried over Na2SO4. Concentration gave a yellow oil, which was dissolved in 20 mL of methanol, and methanesulfonic acid in 5 mL of methanol was added. The reaction mixture was stirred over 50 h under argon prior to being quenched by addition of satd NaHCO3 to pH 7.5. Concentration gave a residue, which was purified by preparative TLC to yield 14 mg of title compound as a white solid. 1H-NMR (CD3OD, 400 MHz) δ 7.48 (s, 1H), 7.36 (s, 1H), 7.03 (s, 4H), 5.93-5.87 (m, 1H), 5.24 (dd, J=17.2 Hz, 1.6 Hz, 1H), 5.11 (dd, J=1.6 Hz, 10.4 Hz, 1H), 4.70 (m, 3H), 4.06-3.89 (m, 4H), 3.82 (dd, J=2.4 Hz, 12.4 Hz, 1H), 3.71-3.62 (m, 2H), 3.50-3.46 (m, 1H), 3.26-3.22 (m, 1H), 3.00 (s, 3H), 2.78-2.74 (m, 1H), 1.12 (d, J=7.2 Hz, 6H); LC-MS (m/z) 493 [(M+1)+].

Provenance & Evidence