[CH2:1]([C@H:9]([C@H:12]([OH:14])[CH3:13])[CH2:10][OH:11])[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6][CH2:7][CH3:8].[OH:15][C:16]1[CH:23]=[CH:22][C:19]([CH:20]=O)=[CH:18][CH:17]=1.S(=O)(=O)(O)O.C(=O)([O-])O.[Na+]>C(OCC)C.O.C1(C)C=CC=CC=1>[CH2:1]([C@H:9]1[CH2:10][O:11][C@H:20]([C:19]2[CH:22]=[CH:23][C:16]([OH:15])=[CH:17][CH:18]=2)[O:14][C@@H:12]1[CH3:13])[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6][CH2:7][CH3:8]A mixture of 320 mg of (2S,3R)-2-octyl-1,3-butanediol, 193 mg of p-hydroxybenzaldehyde, 0.1 ml of 1N sulfuric acid and 20 ml of toluene was placed under nitrogen in a round flask having a magnetic stirrer, water separator and condenser. The mixture was heated to reflux for 3 hours while separating water. The cooled reaction mixture was poured into aqueous sodium hydrogen carbonate solution and treated with diethyl ether. The aqueous phase was separated and extracted three times with diethyl ether. The combined organic phases were washed three times with round flask having a magnetic stirrer, water separator and condenser. The mixture was heated to reflux for 3 hours while separating water. The cooled reaction mixture was poured into aqueous sodium hydrogen carbonate solution and treated with diethyl ether. The aqueous phase was separated and extracted three times with diethyl ether. The combined organic phases were washed three times with water, dried over magnesium sulfate, filtered and evaporated. Recrystallization of the yellowish, solid residue (480 mg) from hexane/ethyl acetate (vol. 25:1) gave 410 mg of 4-[(2S,4R,5S)-5-octyl-4-methyl-1,3-dioxan-2-yl]phenol as yellowish crystals with [a]D =+27° (c=1% in chloroform).
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