Reaction #640394

Reaction equation

potassium tert-butoxide

4-bromobenzothiophene

potassium tert-butoxide

tert-butyl cyanoacetate

hydrochloric acid

→

tert-butyl 2-(1-benzothiophen-4-yl)-2-cyanoacetate

Yield 67.6%

Solvents

1,2-dimethoxyethane

ethyl acetate

water

Conditions

Workup

1. 1
   Temperaturewas then refluxed for 40 minutes
2. 2
   Temperaturewas then refluxed for 30 minutes
3. 3
   OtherThe organic layer was separated
4. 4
   Dryingdried over anhydrous magnesium sulfate
5. 5
   workup.DISTILLATIONby distilling off the solvent under reduced pressure
6. 6
   OtherThe resultant residue was purified

Procedure

To 1,2-dimethoxyethane (3 mL) solution of 0.30 g of 4-bromobenzothiophene were added 0.33 g of potassium tert-butoxide, 0.21 g of tert-butyl cyanoacetate, 0.01 g of dichlorobis(triphenylphosphine)palladium(II) and 0.01 g of triphenylphosphine, which was then refluxed for 40 minutes. Thereto were added 0.33 g of potassium tert-butoxide, 0.01 g of dichlorobis(triphenylphosphine)palladium(II) and 0.01 g of triphenylphosphine, which was then refluxed for 30 minutes. The reaction mixture was added to a mixed solution of water and ethyl acetate, and the pH was adjusted to 1 with 6 mol/L hydrochloric acid. The organic layer was separated, and dried over anhydrous magnesium sulfate, followed by distilling off the solvent under reduced pressure. The resultant residue was purified using silica gel column chromatography (eluent; hexane:ethyl acetate=5:1) to provide 0.26 g of tert-butyl 2-(1-benzothiophen-4-yl)-2-cyanoacetate as pale brown oily form.

Source