Borane → (3-Chloro-1-benzothien-2-yl)methanol

Participants

Reaction Steps

To a solution of 3-chloro-benzo[b]thiophene-2-carboxylic acid (3.5 g, 16.6 mmol) in THF (40 mL) at 0° C. was added drop-wise 1M borane in THF (33 mL, 33.2 mmol) via a dropping funnel. The mixture was stirred at r.t overnight. The reaction was quenched with drop-wise addition of water (6 mL). Solvent was evaporated in vacuo and the residue was partitioned between sat. sodium carbonate and ethyl acetate. The aqueous phase was extracted with ethyl acetate (100 mL), the combined organic phases was washed with water (3×100 mL), dried and concentrated to give (3-chloro-benzo[b]thiophen-2-yl)-methanol as a light yellow solid (3.4 g, 103% crude yield); 1H NMR (DMSO-d6) δ 4.8 (d, J=5.8 Hz, 2H, CH2OH), 5.87 (t, J=5.8 Hz, 1H, CH2OH), 7.42-8.04 (m, 4H, Ar). The product was used in the next step without further purification.

Provenance & Evidence