[Mg].Br[CH2:3][CH2:4][CH2:5][C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.[Br-].[CH3:13][C:14]([CH3:16])=[O:15].Cl>CCOCC>[OH:15][C:14]([CH3:16])([CH2:3][CH2:4][CH2:5][C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)[CH3:13]To a mixture of magnesium turnings 13.16 g (0.541 mol) in 200 ml of anhydrous Et2O was added 100.0 g (0.492 mol) of 1-bromo-3-phenyl propane as a solution in 100 ml of Et2O. After of 5-10 ml of the solution had been added, the addition was stopped until the formation of the Grignard reagent was in progress. The remaining bromide was then added over 1 hour. The Grignard reagent was stirred for 20 minutes at 35° C. and then 31.64 g (0.541 mol) of acetone was added over a 45 minute period. The reaction was stirred overnight at room temperature before being cooled to 0° C. and acidified by the careful addition of 20% HCl. The aqueous layer was extracted with Et2O (3×200 ml) and the combined organic layers washed with water, and saturated aqueous NaCl before being dried over MgSO4. Removal of the solvent under reduced pressure and distillation of the residue afforded 63.0 g (72%) of the product as a pale-yellow oil, bp 99-102° C./10.5 mm Hg. 1H NMR (CDCl3): δ 7.28-7.18 (5H, m), 2.63 (2H, t, J=7.5 Hz), 1.68 (2H, m), 1.52 (2H, m), 1.20 (6H, s).
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