Boron trifluoride → 4-benzyl-6-[2-bromo-5-((2S,3S,4R,5R,6R)-3,4,5-tris-benzyloxy-6-benzyloxymethyl-tetrahydro-pyran-2-yl)-benzyl]-3,4-dihydro-2H-benzo[1,4]oxazine

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of (3R,4S,5R,6R)-2-[3-(4-benzyl-3,4-dihydro-2H-benzo[1,4]oxazin-6-ylmethyl)-4-bromo-phenyl]-3,4,5-tris-benzyloxy-6-benzyloxymethyl-tetrahydro-pyran-2-ol (1.60 g, 1.72 mmol) in acetonitrile-dichloromethane mixture (3:1 mixture, 7 mL) was added triethylsilane (0.82 mL, 5.15 mmol) followed by boron trifluoride diethyletharate complex (0.42 mL, 3.43 mmol) at −30° C. After stirring for 2 h at 0° C., the reaction was quenched with aq. sodium bicarbonate (4 mL). The volatiles were evaporated under reduced pressure, and the resulting mixture was extracted with dichloromethane (2×20 mL). The organic layers were combined and washed with brine (3 mL), dried over sodium sulfate, then concentrated to a residue which was purified by column chromatography to furnish 4-benzyl-6-[2-bromo-5-((2S,3S,4R,5R,6R)-3,4,5-tris-benzyloxy-6-benzyloxymethyl-tetrahydro-pyran-2-yl)-benzyl]-3,4-dihydro-2H-benzo[1,4]oxazine (1.10 g).

Provenance & Evidence