Carbon Dioxide → 3-hexyl-5,5-dimethyl-6,7,8,9-tetrahydro-5H-benzocycloheptene-2-carboxylic acid

HRID 1638

Reaction equation

HRID 1638 reaction equation
Br[C:2]1[C:3]([CH2:15][CH2:16][CH2:17][CH2:18][CH2:19][CH3:20])=[CH:4][C:5]2[C:11]([CH3:13])([CH3:12])[CH2:10][CH2:9][CH2:8][CH2:7][C:6]=2[CH:14]=1.[Li]CCCC.[C:26](=[O:28])=[O:27]>O1CCCC1>[CH2:15]([C:3]1[C:2]([C:26]([OH:28])=[O:27])=[CH:14][C:6]2[CH2:7][CH2:8][CH2:9][CH2:10][C:11]([CH3:13])([CH3:12])[C:5]=2[CH:4]=1)[CH2:16][CH2:17][CH2:18][CH2:19][CH3:20]

Participants

5

Reactant 3

HCID 280Carbon DioxideHCID 218467192-bromo-3-hexyl-5,5-dimethyl-6,7,8,9-tetrahydro-5H-benzocyclohepteneHCID 178418339Butyllithium

Product 1

HCID 218467053-hexyl-5,5-dimethyl-6,7,8,9-tetrahydro-5H-benzocycloheptene-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

This 3.21 g of 2-bromo-3-hexyl-5,5-dimethyl-6,7,8,9-tetrahydro-5H-benzocycloheptene were placed in 30 ml of abs. tetrahydrofuran under Ar and treated at -78° with 6.75 ml of 1.55M nBuLi (hexane) (1.1 eq.). The metal/halogen exchange was followed by gas chromatography (GC). After 40 min., a large excess of CO2 gas was introduced and the cooling bath was removed. After 10 min., the mixture was poured on to ice/NH4Cl solution, extracted with diethyl ether, washed with H2O, dried over Na2SO4 and the solvent was removed in a vacuum. Flash chromatography on SiO2 (hexane/ethyl acetate=8/2) yielded 2.26 g of 3-hexyl-5,5-dimethyl-6,7,8,9-tetrahydro-5H-benzocycloheptene-2-carboxylic acid as white crystals of m.p. 74°-75°.

Workup

  1. customthe cooling bath was removed
  2. waitAfter 10 min.
  3. additionthe mixture was poured on to ice/NH4Cl solution
  4. extractionextracted with diethyl ether
  5. washwashed with H2O
  6. dry with materialdried over Na2SO4
  7. customthe solvent was removed in a vacuum

Sources & evidence

ORD record
ord-bec0b13badfd4aa9b7a9fafcead8a865
Source dataset
uspto-grants-1998_03
Patent number
US05726191

Linked notes

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