5-(2,2-Dibromo-vinyl)-benzo[1,3]dioxole → 5-Ethynylbenzo-1,3-dioxole

HRID 24025Notes

Reaction equation

HRID 24025 reaction equation
Br[C:2](Br)=[CH:3][C:4]1[CH:12]=[CH:11][C:7]2[O:8][CH2:9][O:10][C:6]=2[CH:5]=1.C([Li])CCC>C1COCC1>[C:3]([C:4]1[CH:12]=[CH:11][C:7]2[O:8][CH2:9][O:10][C:6]=2[CH:5]=1)#[CH:2]

Participants

4

Reactant 2

HCID 109687645-(2,2-Dibromo-vinyl)-benzo[1,3]dioxoleHCID 178418339Butyllithium

Product 1

HCID 926805-Ethynylbenzo-1,3-dioxoleYield 95%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 5-(2,2-dibromo-vinyl)-benzo[1,3]dioxole (1.47 g, 5.0 mmol) in THF (10 mL) at −78° C. was added 2.0 M solution of n-butyllithium (5.5 mL, in cyclohexane) over 5 minutes period. After the addition completed, the reaction was stirred for 1 h, and then quenched with saturated NH4Cl. The mixture was allowed to warm up to room temperature. THF was removed. The aqueous was extracted with ethyl acetate. The organic layer was washed with water, brine, dried over Na2SO4, concentrated, and flash chromatographed on silica gel, eluting with DCM/hexane (5 to 10%) to give the title compound (0.64 g, 95% yield) as an orange oil. 1H NMR (CDCl3) δ 7.02 (dd, 1H, J=1.6, 8.1 Hz), 6.93 (d, 1H, J=1.6 Hz), 6.75 (d, 1H, J=8.0 Hz), 5.98 (s, 2H), 2.97 (s, 1H).

Workup

  1. additionAfter the addition
  2. customquenched with saturated NH4Cl
  3. customTHF was removed
  4. extractionThe aqueous was extracted with ethyl acetate
  5. washThe organic layer was washed with water, brine
  6. dry with materialdried over Na2SO4
  7. concentrationconcentrated
  8. customflash chromatographed on silica gel
  9. washeluting with DCM/hexane (5 to 10%)

Sources & evidence

ORD record
ord-b0014927d05645dc9b18479c63c7bf9b
Source dataset
uspto-grants-2005_02
Patent number
US06855722B2

Reaction notes

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