C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[Br:20]Br.[F:22][C:23]1[CH:24]=[C:25]2[C:30](=[CH:31][C:32]=1[CH2:33]O)[O:29][CH2:28][CH:27]([CH2:35][CH2:36][CH2:37][CH2:38][CH3:39])[CH2:26]2.O>C(#N)C>[Br:20][CH2:33][C:32]1[CH:31]=[C:30]2[C:25]([CH2:26][CH:27]([CH2:35][CH2:36][CH2:37][CH2:38][CH3:39])[CH2:28][O:29]2)=[CH:24][C:23]=1[F:22]10.2 g (38.9 mmol) of triphenylphosphine are suspended in 80 ml of acetonitrile, and 2.0 ml (39.0 mmol) of bromine are added dropwise with ice cooling. A solution of 10.0 g (38.4 mmol) of (6-fluoro-3-pentylchroman-7-yl)methanol in 20 ml of acetonitrile is subsequently added, and the mixture is stirred overnight at room temp. After addition of water, the mixture is extracted three times with n-heptane, and the combined org. phases are washed with water and dried over sodium sulfate. The solvent is removed in vacuo, and the residue is filtered through silica gel with heptane/toluene (4:1), giving 7-bromomethyl-6-fluoro-3-pentylchroman as a colourless oil.
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