P(Br)(Br)(Br)(Br)Br.[Br:7]Br.P(Br)(Br)Br.[C:13]1([CH2:19][CH2:20][CH2:21][CH:22](O)[CH3:23])[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.[Cl-]>C(Cl)Cl.O>[Br:7][CH:22]([CH2:21][CH2:20][CH2:19][C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1)[CH3:23]To phosphorus pentabromide, prepared by addition of bromine (9.0 g.) in methylene chloride (10 ml.) to phosphorous tribromide (15.0 g.) in methylene chloride (15 ml.) at 0° C., is added 5-phenyl-2-pentanol (8.2 g.) in metnhylene chloride at 0° C. The mixture is stirred for 2.5 hours at 0° C. and is then allowed to warm to room temperature. Water (50 ml.) is added, the mixture stirred for 1 hour and the methylene chloride layer separated. The extraction is repeated and the combined extracts washed with water, saturated sodium bicarbonate solution, brine and then dried over magnesium sulfate. Concentration of the dried extracts gives 12.4 g. of title product as a light yellow oil.
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