Ethyl 2-thienylacetate → 1-Thiophen-2-yl-cyclopent-3-ene carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of thiophen-2-yl acetic acid ethyl ester (1) (980 mg, 5.76 mmol) in 10 ml of THF at -20° C. was added a 1M solution of potassium t-butoxide in THF (5.76 ml, 5.76 mM) over 15 minutes. After 30 minutes at -20° C., cis-1,4-dichlorobut-2-ene (0.610 ml, 5.76 mmol) was added dropwise and the reaction was warmed to room temperature. After 20 minutes the reaction was recooled to -20° C. and treated with potassium t-butoxide in THF (5.76 ml, 5.76 mM). The reaction was allowed to warm to room temperature, then was heated at 50° C. for 30 minutes and quenched with saturated ammonium chloride solution. The solvents were removed in vacuo and the residue taken up in EtOAc and washed with water. The organic layer was washed with saturated sodium chloride and dried over MgSO4 to yield the title compound (2) (450 mg) after chromatography on silica gel using 5% EtOAc in hexanes as the eluant.

Provenance & Evidence