Monobenzone → Benzo(B)Thiophene

Participants

Reaction Steps

To a solution of 3-bromo-benzo[b]thiophene (69.62 g, 0.325 mol) in 55 mL of anhydrous 2,4,6-collidine under N2 is added 4-benzyloxyphenol (97.6 g, 0.488 mol) and cuprous oxide (23.3 g, 0.163 mol). The mixture is heated to reflux for 24 hours. Upon cooling, the reaction mixture is diluted with ethyl acetate (200 mL) and the crude mixture is filtered through a pad of Celite® (Aldrich, Milwaukee, Wis.) to remove inorganic salts. The filtrate is washed with 1N hydrochloric acid (3×150 mL). The organic is dried (sodium sulfate) and concentrated in vacuo to a liquid. Thianaphthene was removed by distillation (10 mm Hg, 115-120° C.). The remainder of the material is chromatographed (silicon dioxide, hexanes: ethyl acetate 85:15) to provide 12.2 g of benzo[b]thiophene and 12.95 g (35% based on recovered starting material) of 3-(4-benzyloxy)phenoxybenzo[b]thiophene as an off-white solid.

Provenance & Evidence