1,1-Dibromoethane → HCID 68840238, compound

HRID 2110604Notes

Reaction equation

HRID 2110604 reaction equation
[Mg].Cl[CH2:3][CH2:4][C:5]([CH3:8])([CH3:7])[CH3:6].BrC(Br)C.[OH:13][C:14]1[C:15](=[O:25])[C:16]2[C:21]([C:22](=[O:24])[CH:23]=1)=[CH:20][CH:19]=[CH:18][CH:17]=2>O1CCCC1.C(OCC)(=O)C.CC(C)[O-].[Ti+4].CC(C)[O-].CC(C)[O-].CC(C)[O-]>[CH3:6][C:5]([CH3:8])([CH3:7])[CH2:4][CH2:3][C:15]1([OH:25])[C:16]2[C:21](=[CH:20][CH:19]=[CH:18][CH:17]=2)[C:22](=[O:24])[CH2:23][C:14]1=[O:13]

Participants

8

Reactant 4

HCID 112011,1-Dibromoethane2×HCID 761111-Chloro-3,3-dimethylbutaneHCID 5462224MagnesiumHCID 178516607HCID 178516607, compound

Product 1

HCID 68840238HCID 68840238, compoundYield 28%

Reagents, catalysts & solvents 3

HCID 11026Titanium isopropoxideCatalystHCID 8028TetrahydrofuranSolvent3×HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
0 °C

Procedure

To a suspension of magnesium turnings (2.90 g, 0.12 mol) in tetrahydrofuran (150 mL) was added 1-chloro-3,3-dimethylbutane (14.2 g, 0.12 mol). The mixture was cooled to 0° C. and dibromoethane (2.5 mL, 29 mmol) was added portion wise over 15 min. The mixture was allowed to warm to room temperature and stirred for 1 h. After which, an additional equivalent of dibromoethane (2.5 mL, 29 mmol) was added portion wise over 15 min and stirred at room temperature for 72 h. The mixture was diluted with tetrahydrofuran (50 mL) cooled to −78° C., and treated with titanium(IV) isopropoxide (33.9 mL, 0.11 mol). The reaction mixture was stirred at −78° C. for 1 h and a solution of 2-hydroxy-1,4-naphthoquinone (5.0 g, 29 mmol) in tetrahydrofuran (80 mL) pre-cooled to 0° C. was added via a cannula. After addition, the solution was warmed to room temperature and stirred for 18 h. The solution was diluted with ethyl acetate (250 mL) and washed with aqueous 1 N HCl (2×100 mL). The organic layer was dried (Na2SO4) and concentrated in vacuo. Column chromatography on florisil (dichloromethane→1%→3→%5% methanol/dichloromethane) followed by second column chromatography on silica (30%→50% ethyl acetate/hexane) afforded the title compound as an orange amorphous solid (2.06 g, 28%). 1H NMR (300 MHz, DMSO-d6), δ ppm 0.33-0.52 (m, 1H), 0.68 (s, 9H), 0.77-0.92 (m, 1H), 1.67-1.84 (m, 1H), 1.88-2.11 (m, 1H), 5.56 (s, 1H), 7.36-7.45 (m, 1H), 7.57 (t, J=6.99 Hz, 1H), 7.62-7.68 (m, 1H), 7.82 (d, J=6.62 Hz, 1H); MS m/z 261.1 (M+H)+.

Workup

  1. temperatureto warm to room temperature
  2. stirringstirred at room temperature for 72 h
  3. temperaturecooled to −78° C.
  4. stirringThe reaction mixture was stirred at −78° C. for 1 h
  5. additionwas added via a cannula
  6. additionAfter addition
  7. temperaturethe solution was warmed to room temperature
  8. stirringstirred for 18 h
  9. washwashed with aqueous 1 N HCl (2×100 mL)
  10. dry with materialThe organic layer was dried (Na2SO4)
  11. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-7d823edfde144f40a9b582f68047a3aa
Source dataset
uspto-grants-2009_04
Patent number
US07517876B2

Reaction notes

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