COC[O:4][C:5]1[CH:10]=[C:9]([O:11]COC)[CH:8]=[CH:7][C:6]=1[C@H:15]1[CH2:20][CH2:19][C@H:18]([CH2:21][C:22]([O:24][CH3:25])=[O:23])[CH2:17][CH2:16]1.CO.Cl.C(=O)(O)[O-].[Na+]>O.C(OCC)(=O)C>[OH:4][C:5]1[CH:10]=[C:9]([OH:11])[CH:8]=[CH:7][C:6]=1[C@H:15]1[CH2:16][CH2:17][C@H:18]([CH2:21][C:22]([O:24][CH3:25])=[O:23])[CH2:19][CH2:20]1To a round bottomed flask equipped with magnetic stirrer was added cis/trans-methyl {4-[2,4-bis(methoxymethoxy)phenyl]cyclohexyl}acetate (1.00 g, 2.84 mmol) and methanol (20 ml). The stirred solution was heated to reflux temperature and aqueous hydrochloric acid (20 ml, 1 M) was added in aliquots (4×5 ml) at 10 min intervals. After 2 hr, the reaction mixture was cooled to room temperature and saturated aqueous sodium bicarbonate (50 ml) added. The reaction mixture was poured into a separating funnel containing ethyl acetate (100 ml) and water (30 ml). The layers were separated and the aqueous layer was extracted with ethyl acetate (3×30 ml). The combined organic layers were washed with brine (20 ml), dried over magnesium sulfate, filtered and concentrated in vacuo to give a white solid. Purification via flash column chromatography (SiO2, ethyl acetate/petroleum ether, 1:2, v/v) afforded the title compound (0.51 g, 69%) as a mixture of diastereoisomers. m/z (ES+) 265 (M+H+); δH(CD3OD) 1.33-1.91 (9H, m), 2.30 (2H, m), 2.79 (1H, m), 3.72 (3H, s), 6.28 (2H, m), 6.95 (1H, m).
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