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

HRID 72616Notes

Reaction equation

[CH2:1]([N:8]1[C:13]2[CH:14]=[C:15]([CH2:18][C:19]3[CH:20]=[C:21]([C:26]4(O)[C@H:31]([O:32][CH2:33][C:34]5[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=5)[C@@H:30]([O:40][CH2:41][C:42]5[CH:47]=[CH:46][CH:45]=[CH:44][CH:43]=5)[C@H:29]([O:48][CH2:49][C:50]5[CH:55]=[CH:54][CH:53]=[CH:52][CH:51]=5)[C@@H:28]([CH2:56][O:57][CH2:58][C:59]5[CH:64]=[CH:63][CH:62]=[CH:61][CH:60]=5)[O:27]4)[CH:22]=[CH:23][C:24]=3[Br:25])[CH:16]=[CH:17][C:12]=2[O:11][CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C([SiH](CC)CC)C.B(F)(F)F>C(#N)C.ClCCl>[CH2:1]([N:8]1[C:13]2[CH:14]=[C:15]([CH2:18][C:19]3[CH:20]=[C:21]([C@H:26]4[C@H:31]([O:32][CH2:33][C:34]5[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=5)[C@@H:30]([O:40][CH2:41][C:42]5[CH:43]=[CH:44][CH:45]=[CH:46][CH:47]=5)[C@H:29]([O:48][CH2:49][C:50]5[CH:51]=[CH:52][CH:53]=[CH:54][CH:55]=5)[C@@H:28]([CH2:56][O:57][CH2:58][C:59]5[CH:60]=[CH:61][CH:62]=[CH:63][CH:64]=5)[O:27]4)[CH:22]=[CH:23][C:24]=3[Br:25])[CH:16]=[CH:17][C:12]=2[O:11][CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

Conditions

Temperature: 0 °C

Procedure

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).

Workup

customthe reaction was quenched with aq. sodium bicarbonate (4 mL)
customThe volatiles were evaporated under reduced pressure
extractionthe resulting mixture was extracted with dichloromethane (2×20 mL)
washwashed with brine (3 mL)
dry with materialdried over sodium sulfate
concentrationconcentrated to a residue which
customwas purified by column chromatography

Sources & evidence

ORD record: ord-74ef18b3d1fb452c835f383fd928c3b7
Source dataset: uspto-grants-2014_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08828951B2

Reaction notes

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