Sodium Carbonate → 2-t-Butyldimethylsilyl-3-(t-butyldimethylsilyloxymethylene)-6-methoxy-7-isopropoxybenzofuran

HRID 529235Notes

Reaction equation

HRID 529235 reaction equation
[CH:1]([O:4][C:5]1[C:10]([O:11][CH3:12])=[CH:9][C:8](I)=[CH:7][C:6]=1[OH:14])([CH3:3])[CH3:2].[Si:15]([C:22]#[C:23][CH2:24][O:25][Si:26]([C:29]([CH3:32])([CH3:31])[CH3:30])([CH3:28])[CH3:27])([C:18]([CH3:21])([CH3:20])[CH3:19])([CH3:17])[CH3:16].[Cl-].[Li+].C(=O)([O-])[O-].[Na+].[Na+]>CN(C)C=O.C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[Si:15]([CH:22]1[C:23](=[CH:24][O:25][Si:26]([C:29]([CH3:32])([CH3:31])[CH3:30])([CH3:27])[CH3:28])[C:7]2[CH:8]=[CH:9][C:10]([O:11][CH3:12])=[C:5]([O:4][CH:1]([CH3:2])[CH3:3])[C:6]=2[O:14]1)([C:18]([CH3:21])([CH3:20])[CH3:19])([CH3:17])[CH3:16]

Participants

7

Reactant 4

HCID 10340Sodium CarbonateHCID 433294Lithium ChlorideHCID 10968062HCID 10968062, compoundHCID 57421943HCID 57421943, compound

Product 1

HCID 670422652-t-Butyldimethylsilyl-3-(t-butyldimethylsilyloxymethylene)-6-methoxy-7-isopropoxybenzofuranYield 96%

Reagents, catalysts & solvents 2

HCID 167845palladium(II) acetateCatalystHCID 6228DimethylformamideSolvent

Procedure

A suspension of 2-isopropoxy-3-methoxy-5-iodophenol (4.41 mmol), 1-(tert-butyldimethylsilyl)-3-(tert-butyldimethylsilyloxy)propyne (1.5 g, 5.28 mmol), lithium chloride (189 mg, 4.45 mmol) and sodium carbonate (2.34 g, 22.08 mmol) in dry dimethylformamide (5 mL) at 100° C. was deoxygenated 4 times by evacuation and backfilling with nitrogen. Palladium acetate (135 mg, 0.60 mmol) was added and the reaction vessel was degassed twice with nitrogen. The reaction mixture was then stirred at this temperature for 4 hours (tlc) and the solvent was removed by distillation under vacuum. The residue was dissolved in ethyl acetate (75 mL), stirred well, filtered and treated with triethylamine (5 mL). The solution was concentrated onto silica gel (10 g) and purified by flash chromatography (silica gel, eluent=hexane/diethyl ether/triethylamine; 95:5:1%) to afforded the title compound as a yellow oil (1.45 g, 96%); 1H NMR (300 MHz, CDCl3) δ 7.24 (d, 1H, J=8.45 Hz), 6.88 (d, 1H, J=8.47 Hz), 4.80 (s, 2H, CH2), 4.73 (m, 1H), 3.88 (s, 3H, OMe), 1.36 (d, 6H, J=6.17 Hz), 0.94 (s, 9H), 0.92 (s, 9H), 0.35 (s, 6H), 0.12 (s, 6H).

Workup

  1. customwas deoxygenated 4 times by evacuation and backfilling with nitrogen
  2. customthe reaction vessel was degassed twice with nitrogen
  3. customthe solvent was removed by distillation under vacuum
  4. dissolutionThe residue was dissolved in ethyl acetate (75 mL)
  5. stirringstirred well
  6. filtrationfiltered
  7. additiontreated with triethylamine (5 mL)
  8. concentrationThe solution was concentrated onto silica gel (10 g)
  9. custompurified by flash chromatography (silica gel, eluent=hexane/diethyl ether/triethylamine; 95:5:1%)

Sources & evidence

ORD record
ord-d36aa6cf56ec48f396311554c266d688
Source dataset
uspto-grants-2016_05
Patent number
US09346842B2

Reaction notes

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