Dibromomethane → HCID 19428661, compound

HRID 1079000Notes

Reaction equation

HRID 1079000 reaction equation
BrCBr.O1CCC[CH2:5]1.[Si:9]([O:16][CH:17]1[CH2:21][C:20](=O)[C:19]([CH2:23][CH:24]=[CH2:25])=[C:18]1[CH3:26])([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10].C(=O)(O)[O-].[Na+]>ClCCl.CCCCC.[Zn].[Ti](Cl)(Cl)(Cl)Cl.O>[CH3:26][C:18]1[CH:17]([O:16][Si:9]([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10])[CH2:21][C:20](=[CH2:5])[C:19]=1[CH2:23][CH:24]=[CH2:25]

Participants

10

Reactant 4

HCID 3024DibromomethaneHCID 8028Tetrahydrofuran2×HCID 516892Sodium BicarbonateHCID 19428659HCID 19428659, compound

Product 1

HCID 19428661HCID 19428661, compoundYield 88.4%

Reagents, catalysts & solvents 5

HCID 23994ZincCatalystHCID 24193Titanium TetrachlorideCatalystHCID 962WaterSolventHCID 6344DichloromethaneSolvent2×HCID 8003PentaneSolvent

Procedure

2 Dibromomethane (6.13 g) and zinc dust (6.92 g) were added to dry tetrahydrofuran (100 ml), and the resulting mixture was cooled to 0°~5° C. A dichloromethane solution (25.9 ml) of 1M titanium tetrachloride was added to the tetrahydrofuran solution in about 10 min, and the resulting mixture was allowed to react for 4 days at 0°~5° C. Then a solution of (RS)-4-tert-butyldimethylsilyloxy-3-methyl-2-(2-propenyl)cyclopent-2-ene-1-one (6.27 g) in dichloromethane (30 ml) was added at 0°5° C. in about 10 min. After the mixture was allowed to react for 12 hours at the same temperature, the reaction mixture was diluted with pentane (150 ml), and then a slurry consisting of sodium bicarbonate (150 g) and water (80 ml) was slowly added. After stirring for 2 hours at the same temperature, the reaction mixture was filtered by passing through a celite pad, and the separated layer was dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure. The resultant residue was subjected to silica gel column chromatography (eluent; n-hexane: ethyl acetate=50:1) to afford the desired product, (RS)-2-methyl-4-methylidene-3-(2-propenyl)-1-tert-butyldimethylsilyloxycyclopent-2-ene (5.5 g, yield 88.4%) as a pale yellow oil.

Workup

  1. temperaturethe resulting mixture was cooled to 0°~5° C
  2. customto react for 4 days at 0°~5° C
  3. customto react for 12 hours at the same temperature
  4. additionwas slowly added
  5. filtrationthe reaction mixture was filtered
  6. dry with materialthe separated layer was dried over anhydrous sodium sulfate
  7. customThe solvent was evaporated under reduced pressure

Sources & evidence

ORD record
ord-b9256156f93c4d1a84ff9749ecc296d3
Source dataset
uspto-grants-1996_08
Patent number
US05550260

Reaction notes

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