Boron tribromide → (1R,10R,11S,16S)-1,11,15,15-tetramethyl-8-oxatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene-4,6-diol
Reaction equation
C[O:2][C:3]1[CH:4]=[C:5]2[C:18](=[C:19]([O:21]C)[CH:20]=1)[O:17][CH2:16][C@H:15]1[C@@:6]2([CH3:26])[CH2:7][CH2:8][C@@H:9]2[C@:14]1([CH3:23])[CH2:13][CH2:12][CH2:11][C:10]2([CH3:25])[CH3:24].B(Br)(Br)Br>C(Cl)Cl>[CH3:26][C@@:6]12[CH2:7][CH2:8][C@@H:9]3[C@:14]([CH3:23])([CH2:13][CH2:12][CH2:11][C:10]3([CH3:24])[CH3:25])[C@H:15]1[CH2:16][O:17][C:18]1[C:5]2=[CH:4][C:3]([OH:2])=[CH:20][C:19]=1[OH:21]Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of (1R,10R,11S,16S)-4,6-dimethoxy-1,11,15,15-tetramethyl-8-oxatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene (Compound No. 42) (0.69 g, 1.9 mmol) in CH2Cl2 (20 mL), cooled to 0° C., and a BBr3 solution (7.3 mL, 1 M in CH2Cl2, 7.3 mmol) was added dropwise. The ice bath was removed and the reaction was stirred at room temperature for 6 h. The reaction was quenched with MeOH (20 mL) and concentrated. The quenching and concentration steps were repeated six times. Purification by column chromatography on silica gel (Hexanes/EtOAc, 4:1) gave (1R,10R,11S,16S)-1,11,15,15-tetramethyl-8-oxatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene-4,6-diol (Compound No. 43) (0.42 g, 66%) as a pale pink solid. 1H NMR (CDCl3): δ 6.28 (d, 1H), 6.17 (d, 1H), 5.48 (br s, 1H), 4.40 (m, 1H), 4.25 (br s, 1H), 4.15 (t, 1H), 2.20 (m, 1H), 1.80-1.35 (m, 7H), 1.28 (s, 3H), 1.25-1.00 (m, 4H), 0.92 (s, 3H), 0.88 (s, 3H), 0.82 (s, 3H). MS m/z 331 (C21H30O3+H+).
Workup
- customThe ice bath was removed
- customThe reaction was quenched with MeOH (20 mL)
- concentrationconcentrated
- concentrationThe quenching and concentration steps
- customPurification by column chromatography on silica gel (Hexanes/EtOAc, 4:1)
Sources & evidence
- ORD record
- ord-c0077aaa574844df8631cba9d402772a
- Source dataset
- uspto-grants-2012_01
- Patent number
- US08101605B2
Reaction notes
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