[CH3:1][C:2]1([C:7]2[CH:12]=[CH:11][C:10](Br)=[CH:9][CH:8]=2)[O:6][CH2:5][CH2:4][O:3]1.[Mg].O1CCOC1.[CH3:20][C:21]([CH3:25])([CH3:24])[CH:22]=[O:23]>O1CCCC1>[CH3:1][C:2]1([C:7]2[CH:12]=[CH:11][C:10]([CH:22]([OH:23])[C:21]([CH3:25])([CH3:24])[CH3:20])=[CH:9][CH:8]=2)[O:6][CH2:5][CH2:4][O:3]1In 250 milliliters of tetrahydrofuran, 118 grams of the above dioxolane is dissolved. One quarter of this solution is then added to 12 grams of magnesium previously washed with chloroform, and refluxed with tetrahydrofuran for 20 minutes; and this mixture is refluxed 4 hours to initiate reaction. Additional dioxolane solution is thereafter added to maintain the refluxing without further heating. After the addition has been completed, 35 grams of 2,2-dimethylpropanal is added and the mixture is refluxed for 2 hours. The reactants are allowed to stand overnight and then poured onto ice-cold ammonium chloride solution. Tetrahydrofuran is added and the two layers formed are allowed to separate. The solvent layer is decanted off and the aqueous layer is extracted twice with 100 milliliters of tetrahydrofuran which are decanted off and combined with the remaining solvent layer. The organic phase is dried over anhydrous magnesium sulphate, filtered and evaporated to dryness to yield a yellow oil which is distilled at 120° to 150°C. at 30M and recrystallized from pentane/ether to yield 2-methyl- 2-(4-[1-hydroxy-2,2-dimethylpropyl]-phenyl)-1,3-dioxolane (m.p. 75°-80°C.).
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