p-Toluenesulfonic acid monohydrate → [(1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[3-[(4-benzyloxyphenyl)methyl]-4-chloro-phenyl]-6,8-dioxabicyclo[3.2.1]octan-1-yl]methanol

Participants

Reaction Steps

To a solution of [(3S,4S,5R,6S)-3,4,5-tribenzyloxy-6-[3-[(4-benzyloxyphenyl)methyl]-4-chloro-phenyl]-2-(hydroxymethyl)-6-methoxy-tetrahydropyran-2-yl]methanol 25k (1.04 g, 13 mmol) in dichloromethane (100 mL) was added p-toluenesulfonic acid monohydrate (123 mg, 0.65 mmol) at 0° C. The mixture was warmed up to room temperature and stirred for 16 hours. The reaction mixture was quenched with saturated aqueous sodium bicarbonate (10 mL) and partitioned. The organic layer was washed with water (30 mL×2) and saturated aqueous sodium chloride (30 mL×2) in turn, 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)=10/1 to give the title compound 25l as pale yellow oil (0.59 g, 58.7%). The compound was characterized by the following spectroscopic data: 1H NMR (600 MHz, CDCl3) δ(ppm): 7.44 (m, 3H), 7.35 (m, 15H), 7.19 (m, 3H), 7.09 (m, 2H), 6.89 (m, 2H), 6.85 (m, 2H), 5.02 (s, 2H), 4.90 (d, 2H), 4.86 (d, 1H), 4.77 (d, 1H), 4.30 (d, 1H), 4.27 (d, 1H), 4.07 (d, 1H), 4.03 (m, 2H), 3.97 (d, 1H), 3.86 (d, 1H), 3.82 (d, 1H), 3.74 (d, 1H), 3.70 (d, 1H), 3.68 (d, 1H).

Provenance & Evidence