Iodine → 5-(3,3-Dimethylbut-1-ynyl)-3-iodothiophene-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-(3,3-Dimethyl-but-1-ynyl)-thiophene-2-carboxylic acid (6.2 g, 30 mmol; see U.S. Pat. No. 5,861,421) in THF (100 mL) was added a solution of nBuLi (2.0 M in pentane, 33 mL, 66 mmol) via an addition funnel at −78° C. After addition, the reaction was stirred at −78° C. for 1 h. A solution of I2 (7.7 g, 30 mmol) in THF (100 mL) was added slowly (ca. 15 min) to the flask. After a further 10 mins, the reaction was quenched with 1 N HCl (50 mL) and warmed to room temperature. The volatiles were removed in vacuo and the residue was dissolved in ether (500 mL). The organic solution was washed with 1 M Na2S2O3 (100 mL×2), brine (100 mL) and dried over Na2SO4. After concentrated in vacuo, the residue was purified by silica gel chromatography (EtOAc/hexanes) to give 5-(3,3-Dimethyl-but-1-ynyl)-3-iodo-thiophene-2-carboxylic acid (5.9 g, 65%) as a white solid.

Provenance & Evidence