p-Toluenesulfonic acid monohydrate → (1S,2S,3S,4R,5S)-3,4-dibenzyloxy-5-[4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl]-1-(hydroxymethyl)-6,8-dioxabicyclo[3.2.1]octan-2-ol

Participants

Reaction Steps

To a solution of (4aS,7S,8R,9S,9aS)-8,9-bis(benzyloxy)-7-(4-chloro-3-(4-ethoxybenzyephenye-2-phenylhexahydro-4a,7-epoxy[1,3]dioxino[5,4-c]oxepine 28c (17.56 g, 27.3 mmol) in acetonitrile (40 mL) was added p-toluenesulfonic acid monohydrate (9.4 g, 54.6 mmol) at room temperature. The mixture was stirred at room temperature for 12 hours and adjusted with saturated aqueous sodium bicarnonate till pH becomes 7. The resulting mixture was extracted with ethyl actate (100 mL×3). The combined organic phases 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)=3/1 to give the title compound 28d as a yellow solid (11.68 g, 76.0%). The compound was characterized by the following spectroscopic data: 1H NMR (600 MHz, CDCl3) δ (ppm): 7.35 (d, 1H), 7.29-7.26 (m, 4H), 7.24 (d, 3H), 7.11 (m, 3H), 6.99 (d, 2H), 6.82 (d, 2H), 6.67 (d, 2H), 4.79 (d, 1H), 4.62 (d, 1H), 4.15 (m, 2H), 3.99 (d, 1H), 3.90 (m, 4H), 3.76 (m, 4H), 3.57 (d, 2H), 1.31 (t, 3H).

Provenance & Evidence