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 patent application U.S. Pat. No. 5,861,421) in THF (100 mL) was added a solution of nBuLi (2.0M 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 1N 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 1M 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