Methyl iodide → 1-[4-(t-Butyldimethylsilyl)oxy-2,6,6-trimethylcyclohex-1-enyl]pent-1-en-3-one

HRID 703624Notes

Reaction equation

HRID 703624 reaction equation
[CH:1](NC(C)C)(C)C.C([Li])CCC.[Li+].CC([N-]C(C)C)C.[Si:21]([O:28][CH:29]1[CH2:34][C:33]([CH3:36])([CH3:35])[C:32]([CH:37]=[CH:38][C:39](=[O:41])[CH3:40])=[C:31]([CH3:42])[CH2:30]1)([C:24]([CH3:27])([CH3:26])[CH3:25])([CH3:23])[CH3:22].CI.[Cl-].[NH4+]>C1COCC1.CN(C)P(=O)(N(C)C)N(C)C.CCCCCC>[Si:21]([O:28][CH:29]1[CH2:34][C:33]([CH3:35])([CH3:36])[C:32]([CH:37]=[CH:38][C:39](=[O:41])[CH2:40][CH3:1])=[C:31]([CH3:42])[CH2:30]1)([C:24]([CH3:27])([CH3:26])[CH3:25])([CH3:23])[CH3:22]

Participants

10

Reactant 6

HCID 6328Methyl iodideHCID 7912DiisopropylamineHCID 25517Ammonium ChlorideHCID 2724682Lithium diisopropylamideHCID 541718584-[4-(t-Butyldimethylsilyl)oxy-2,6,6-trimethylcyclohex-1-enyl]but-3-en-2-oneHCID 178418339Butyllithium

Product 1

HCID 545626981-[4-(t-Butyldimethylsilyl)oxy-2,6,6-trimethylcyclohex-1-enyl]pent-1-en-3-oneYield 63%

Reagents, catalysts & solvents 3

HCID 8028TetrahydrofuranSolvent3×HCID 8058HexaneSolventHCID 12679HexamethylphosphoramideSolvent

Conditions

Temperature
-78 °C

Procedure

To 3 ml of an anhydrous THF solution containing 375 mg of diisopropylamine was added 2.3 ml of a 1.6M n-hexane solution of n-butyl lithium at 0° C. in a nitrogen atmosphere to prepare LDA in the usual manner. The reaction mixture was cooled to -78° C., and 111 mg of hexamethylphosphoric triamide was added thereto. To the cooled mixture was dropwise added 10 ml of an anhydrous THF solution containing 1.0 g of 4-[4-(t-butyldimethylsilyl)oxy-2,6,6-trimethylcyclohex-1-enyl]-but-3-en-2-one. After the dropwise addition, the mixture was stirred under the same condition for 30 minutes. Then, 5 ml of an anhydrous THF solution of 659 mg of methyl iodide was added dropwise thereto. The reaction mixture was warmed to 0° C., followed by stirring overnight. After completion of the reaction, the reaction mixture was poured into a saturated ammonium chloride aqueous solution and extracted with diethyl ether. The organic layer was washed successively with a saturated sodium chloride aqueous solution and water, and dried over anhydrous magnesium sulfate. The solvent, etc. were removed by distillation under reduced pressure. Purification of the residue by silica gel column chromatography yielded 657 mg (63%) of 1-[4-(t-butyldimethylsilyl)oxy-2,6,6-trimethylcyclohex-1-enyl]pent-1-en-3-one.

Workup

  1. additionAfter the dropwise addition
  2. temperatureThe reaction mixture was warmed to 0° C.
  3. stirringby stirring overnight
  4. customAfter completion of the reaction
  5. extractionextracted with diethyl ether
  6. washThe organic layer was washed successively with a saturated sodium chloride aqueous solution and water
  7. dry with materialdried over anhydrous magnesium sulfate
  8. customThe solvent, etc. were removed by distillation under reduced pressure
  9. customPurification of the residue by silica gel column chromatography

Sources & evidence

ORD record
ord-8eb0fc5114e045fdb146de52b9ec7f48
Source dataset
uspto-grants-1991_01
Patent number
US04983723

Reaction notes

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