6-Bromo-1,1,4,4,7-pentamethyl-1,2,3,4-tetrahydronaphthalene → HCID 10991859, compound

HRID 1739731Notes

Reaction equation

HRID 1739731 reaction equation
Br[C:2]1[C:11]([CH3:12])=[CH:10][C:9]2[C:8]([CH3:14])([CH3:13])[CH2:7][CH2:6][C:5]([CH3:16])([CH3:15])[C:4]=2[CH:3]=1.[C:17]([Li])(C)(C)[CH3:18].FC(F)(F)S(O[C:28]1[CH2:33][CH2:32][CH2:31][CH2:30][C:29]=1[C:34]([O-:36])=[O:35])(=O)=O>O1CCCC1.[Cl-].[Zn+2].[Cl-].C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[CH2:17]([O:36][C:34]([C:29]1[CH2:30][CH2:31][CH2:32][CH2:33][C:28]=1[C:2]1[C:11]([CH3:12])=[CH:10][C:9]2[C:8]([CH3:14])([CH3:13])[CH2:7][CH2:6][C:5]([CH3:16])([CH3:15])[C:4]=2[CH:3]=1)=[O:35])[CH3:18]

Participants

7

Reactant 3

HCID 100393466-Bromo-1,1,4,4,7-pentamethyl-1,2,3,4-tetrahydronaphthaleneHCID 21836459HCID 21836459, compoundHCID 178418306HCID 178418306, compound

Product 1

HCID 10991859HCID 10991859, compound

Reagents, catalysts & solvents 3

HCID 3007855ZincchlorideCatalystHCID 178418397HCID 178418397, compoundCatalystHCID 8028TetrahydrofuranSolvent3×

Conditions

Temperature
-78 °C

Procedure

To a stirred (-78° C.) solution of 4.2 g of 2-bromo-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene in 40 ml of tetrahydrofuran is added 18 ml of tert-butyllithium (1.7N in pentane). The reaction mixture is stirred at -78° C. for 1 hour, warmed to room temperature and stirred for 1 hour. Thirty ml of 0.5M zinc chloride solution in tetrahydrofuran is added and the stirring continued for 1 hour. Three grams of 2-trifluoromethanesulfonyloxycyclohexen-1-ylcarboxylate and 0.8 g of tetrakis(triphenylphosphine palladium(O) in tetrahydrofuran is added and the reaction mixture is heated at reflux temperature for 3 hours. Following the reaction work-up of Example 1, 2.75 g of 2-(3,5,5,8,8-pentamethyl-5,6,7,8,-tetrahydro-2-naphthalenyl)-1-cyclohexene-1-carboxylic acid ethyl ester is obtained. The above isolated ester is reduced to the corresponding alcohol with lithium aluminum hydride in diethyl ether, and this is then converted to the triphenylphosphonium bromide as in Example 1. Reaction of the bromide with ethyl 3-methyl-4-oxocrotonate and sodium ethoxide in methylene chloride, as in Example 1, gives the title compound as a mixture of E,E- and Z,E- esters in a 8:1 ratio. The esters are separated into the individual isomers by chromatography.

Workup

  1. temperaturewarmed to room temperature
  2. stirringstirred for 1 hour
  3. waitthe stirring continued for 1 hour
  4. temperaturethe reaction mixture is heated
  5. temperatureat reflux temperature for 3 hours

Sources & evidence

ORD record
ord-11e7ea60af2f4903900a7b63324662e4
Source dataset
uspto-grants-1999_10
Patent number
US05968908

Reaction notes

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