Ethyl isobutyrate → Ethyl 6-bromo-2,2-dimethylhexanoate

HRID 1381916Notes

Reaction equation

HRID 1381916 reaction equation
C([Li])CCC.C(NC(C)C)(C)C.[C:13]([O:18][CH2:19][CH3:20])(=[O:17])[CH:14]([CH3:16])[CH3:15].[Br:21][CH2:22][CH2:23][CH2:24][CH2:25]Br>CCCCCC.O1CCCC1.CN(C)P(N(C)C)(N(C)C)=O>[CH3:15][C:14]([CH3:16])([CH2:25][CH2:24][CH2:23][CH2:22][Br:21])[C:13]([O:18][CH2:19][CH3:20])=[O:17]

Participants

8

Reactant 4

HCID 7342Ethyl isobutyrateHCID 7912DiisopropylamineHCID 80561,4-DibromobutaneHCID 178418339Butyllithium

Product 1

HCID 10444833Ethyl 6-bromo-2,2-dimethylhexanoate

Reagents, catalysts & solvents 3

HCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolventHCID 12679HexamethylphosphoramideSolvent

Conditions

Temperature
-70 °C

Procedure

A solution of n-butyllithium (1.6M, 63 ml, 0.10 mol) in hexane was added dropwise to a solution of diisopropylamine (10.1 g, 0.10 mol) in anhydrous tetrahydrofuran (100 ml) at -50° C. The mixture was stirred for 0.5 hours. The mixture was cooled to -70° C. and a solution of ethyl isobutyrate (12.2 g, 0.105 mol) in tetrahydrofuran (20 ml) was added. The resulting mixture was stirred at -70° C. for 1 hour. 1,4-Dibromobutane (30.4 g, 0.14 mol) was added to the mixture followed by hexamethylphosphoramide (30 g). The resulting mixture was maintained at -70° C. for 0.5 hours and then warmed to room temperature over 1 hour. The solvent was evaporated off under reduced pressure and the residue was treated with saturated aqueous ammonium chloride (500 ml) and extracted with ethyl acetate (2×150 ml). The combined extracts were washed with water (100 ml), hydrochloric acid (1N, 2×100 ml) was saturated aqueous sodium hydrogen carbonate (100 ml) and dried over anhydrous magnesium sulfate. The solvent was evaporated off under reduced pressure and the residue was distilled to yield ethyl 2,2-dimethyl-6-bromohexanoate as a pale yellow oil, having a boiling point of 73° C., 0.06 mm.Hg and the following physical characteristics:

Workup

  1. stirringThe resulting mixture was stirred at -70° C. for 1 hour
  2. temperatureThe resulting mixture was maintained at -70° C. for 0.5 hours
  3. temperaturewarmed to room temperature over 1 hour
  4. customThe solvent was evaporated off under reduced pressure
  5. additionthe residue was treated with saturated aqueous ammonium chloride (500 ml)
  6. extractionextracted with ethyl acetate (2×150 ml)
  7. washThe combined extracts were washed with water (100 ml), hydrochloric acid (1N, 2×100 ml)
  8. dry with materialdried over anhydrous magnesium sulfate
  9. customThe solvent was evaporated off under reduced pressure
  10. distillationthe residue was distilled

Sources & evidence

ORD record
ord-c445a9e2ae9244ce8606eaae2effc9c0
Source dataset
uspto-grants-1989_02
Patent number
US04804658

Reaction notes

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