Boron tribromide → (2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(4-chloro-3-(4- hydroxybenzyl)phenyl)tetrahydro-2H-pyran-3,4,5-triyl triacetate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of acetic acid (2R,3R,4R,5S,6S)-3,4,5-triacetoxy-6-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-tetrahydro-pyran-2-ylmethyl ester (4.0 g, 6.93 mmol) prepared using the procedures described in J. Med. Chem. 2008, 51(5), 1145-49, in dichloromethane (40 mL) was added 1 molar solution of BBr3 (34.6 mL, 34.6 mmol) at −78° C. under nitrogen atmosphere. Reaction was stirred at −78° C. for 1.5 h and −30° C. for 1 h. Reaction mixture was poured over ice and neutralized with sat. NaHCO3 (20 mL), extracted with dichloromethane, concentrated and purified by silica gel column chromatography to furnish acetic acid (2R,3R,4R,5S,6S)-3,4,5-triacetoxy-6-[4-chloro-3-(4-hydroxy-benzyl)-phenyl]-tetrahydro-pyran-2-ylmethyl ester (2.9 g).

Provenance & Evidence