Boron trifluoride → Benzyl 6a-phenyl-3,3a,4,6-tetrahydro-1H-pyrrolo[3,4-c]isoxazole-5-carboxylate

HRID 1618990Notes

Reaction equation

B(F)(F)F.[N:5]1[O:6][CH2:7][CH:8]2[CH2:12][N:11]([C:13]([O:15][CH2:16][C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=3)=[O:14])[CH2:10][C:9]=12.[C:23]1([Mg]Br)[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1>O1CCCC1>[C:23]1([C:9]23[CH2:10][N:11]([C:13]([O:15][CH2:16][C:17]4[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=4)=[O:14])[CH2:12][CH:8]2[CH2:7][O:6][NH:5]3)[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1

Participants

Conditions

Temperature: 0 °C

Procedure

Boron trifluoride (30.8 mL, 244 mmol) is added to a −50° C. solution of benzyl 3,3a,4,6-tetrahydropyrrolo[3,4-c]isoxazole-5-carboxylate (40 g, 162 mmol) in tetrahydrofuran (200 mL). The mixture is stirred for 10 minutes and the solution is added to phenyl magnesium bromide (325 mL, 325 mmol, 1 M in tetrahydrofuran) at −50° C., warmed to 0° C., and stirred for 4 hours. The reaction is quenched with saturated ammonium chloride (200 mL) and the aqueous layer is separated. The organic layer is dried over magnesium sulfate and the solvent is removed under vacuum. The crude product is purified over silica gel using a 5 to 50% ethyl acetate/hexanes gradient to give the title compound (31 g, 59%). ES/MS (m/e): 325 (M+H).

Workup

stirringstirred for 4 hours
customThe reaction is quenched with saturated ammonium chloride (200 mL)
customthe aqueous layer is separated
dry with materialThe organic layer is dried over magnesium sulfate
customthe solvent is removed under vacuum
customThe crude product is purified over silica gel using a 5 to 50% ethyl acetate/hexanes gradient

Sources & evidence

ORD record: ord-f387bde0136d419cbab90fcadb9b7307
Source dataset: uspto-grants-2014_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08772282B2

Reaction notes

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