Iodine → 2-Chloro-5-iodobenzyl alcohol

Participants

Reaction Steps

A 250 mL of 4-necked flask equipped with thermometer and mechanical stirring was charged with NaBH4 (4.16 g, 0.11 mol) and THF (60 mL) under argon. After cooling to 0˜5° C. with stirring, a solution of iodine in THF (12.7 g I2 in 25 mL THF) was added slowly dropwise over 30 min and the reaction temperature was maintained below 10° C. After the addition was completed, a solution of 2-chloro-5-iodobenzoic acid (15.0 g, 50 mmol) in THF (20 mL) was added dropwise over 30 min and kept the reaction temperature below 10° C. After stirring for another 3 h at 20˜25° C., the reaction mixture was heated to reflux for additional 16 h and monitored by TLC (PE/EA=1:1, Rf=0.2). The mixture was cooled to 20˜25° C. and poured into ice water (100 mL), extracted with ethyl acetate (2×100 mL), washed with water (2×100 mL), brine (100 mL), concentrated and the residue was purified by flash chromatography (PE:EA=20:1 as eluant, 200 mL) to give an off-white solid. Yield: 10.0 g (70%) MS ESI (m/z): 269 [M+1]+.

Provenance & Evidence