Reaction #57598

Reaction equation

3-methyl-4-trifluoromethanesulfonyloxy-benzofuran-2-carboxylic acid ethyl ester

vinyl tributyltin

lithium chloride

→

3-methyl-4-vinylbenzofuran-2-carboxylic acid ethyl ester

Yield 75.2%

Solvents

DMF

water

Conditions

Workup

1. 1
   Temperaturecooled to room temperature
2. 2
   Extractionextracted with ether
3. 3
   WashThe combined organics were washed with water and brine
4. 4
   Dryingdried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Concentrationconcentrated in vacuo
7. 7
   OtherThe residue was chromatographed on silica gel eluting with ethyl acetate/hexanes (1:25)

Procedure

To a solution of 2.48 g (7.05 mmol) of 3-methyl-4-trifluoromethanesulfonyloxy-benzofuran-2-carboxylic acid ethyl ester (Example 20, Step 2) in 30 mL of DMF was added 2.16 mL (7.40 mmol) of vinyl tributyltin, 0.898 g (21.1 mmol) of lithium chloride and 0.247 g (0.352 mmol) of tetrakis(triphenylphosphine)palladium(0). The reaction was heated to 90° C. for 3 h and then cooled to room temperature. The reaction was diluted with water and extracted with ether. The combined organics were washed with water and brine, dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with ethyl acetate/hexanes (1:25) to provide 1.22 g of 3-methyl-4-vinylbenzofuran-2-carboxylic acid ethyl ester.

Source