Phenyltrimethylammonium bromide dibromide → 2-Bromo-1-(4-chlorobenzo[b]thiophen-2-yl)butan-1-one
Reaction equation
[Cl:1][C:2]1[C:10]2[CH:9]=[C:8]([C:11](=[O:15])[CH2:12][CH2:13][CH3:14])[S:7][C:6]=2[CH:5]=[CH:4][CH:3]=1.[Br-:16].[Br-].[Br-].C1([N+](C)(C)C)C=CC=CC=1.C1([N+](C)(C)C)C=CC=CC=1.C1([N+](C)(C)C)C=CC=CC=1>O1CCCC1>[Br:16][CH:12]([CH2:13][CH3:14])[C:11]([C:8]1[S:7][C:6]2[CH:5]=[CH:4][CH:3]=[C:2]([Cl:1])[C:10]=2[CH:9]=1)=[O:15]Participants
4
Procedure
A mixture of 1-(4-chlorobenzo[b]thiophen-2-yl)butan-1-one (0.93 g), phenyltrimethylammonium tribromide (1.47 g) and tetrahydrofuran (20 ml) was stirred under nitrogen at ambient temperature for 66 hours, then it was filtered and diluted with water (50 ml). The product was extracted into dichloromethane (3×30 ml), the combined extracts were dried (MgSO4) and the solvents were removed in vacuo. The residue was purified by flash chromatography over silica using dichloromethane as eluant. Appropriate fractions were combined and the solvents removed in vacuo to leave 2-bromo-1-(4-chlorobenzo[b]thiophen-2-yl)butan-1-one (1.07 g) which was used without further purification.