1-(3-bromophenyl)-3-hydroxyhex-5-en-1-one

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 1-(3-bromophenyl)-3-hydroxyhex-5-en-1-one (9.08 g, 33.7 mmol), 1H-imidazole (5.34 g, 77.6 mmol) and tert-butyldimethylchlorosilane (6.29 g, 40.5 mmol) in DMF (40 mL) is stirred at room temperature for 2 h. The mixture is diluted with dichloromethane and is washed sequentially with water and saturated ammonium chloride aqueous solution. The organic layer is dried over sodium sulfate, filtered, and concentrated under reduced pressure. The crude product is purified by silica gel chromatography eluting with a linear gradient of 0% to 5% ethyl acetate in hexanes over 20 minutes to give the title compound as a racemic mixture (11.3 g, 88%). ES/MS m/e (79Br/81Br) 383, 385 (M+1). is washed sequentially with water and saturated ammonium chloride aqueous solution The organic layer is dried over sodium sulfate filtered concentrated under reduced pressure The crude product is purified by silica gel chromatography eluting with a linear gradient of 0% to 5% ethyl acetate in hexanes over 20 minutes

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 1-(3-bromophenyl)hex-5-ene-1,3-diol (2.60 g, 9.59 mmol) and manganese(IV) oxide (9.81 g, 95.9 mmol) in dichloromethane (80 mL) is heated and stirred for 4 h under reflux. The reaction mixture is filtered through a pad of diatomaceous earth and the residue is washed twice with dichloromethane. The filtrate is concentrated under reduced pressure to afford the title compound (2.12 g, 82%). 1H NMR (400 MHz, CDCl3) δ 8.05 (d, 1H, J=1.8 Hz), 7.85 (d, 1H, J=7.5 Hz), 7.69-7.52 (m, 1H), 7.35-7.31 (m, 1H), 5.91-5.82 (m, 1H), 5.18-5.12 (m, 2H), 4.32-4.26 (m, 1H), 3.09-3.00 (m, 2H), 2.39-2.30 (m, 2H). is heated under reflux The reaction mixture is filtered through a pad of diatomaceous earth the residue is washed twice with dichloromethane The filtrate is concentrated under reduced pressure