[C:1]([C:3]1[C:4]([O:16][CH3:17])=[CH:5][C:6]([O:14][CH3:15])=[C:7]([C:9]2[S:10][CH:11]=[CH:12][CH:13]=2)[CH:8]=1)#[CH:2].C([Li])CCC.[CH:23]([C:25]1[CH:34]=[CH:33][C:28]([C:29]([O:31][CH3:32])=[O:30])=[CH:27][CH:26]=1)=[O:24]>C1COCC1>[CH3:32][O:31][C:29](=[O:30])[C:28]1[CH:33]=[CH:34][C:25]([CH:23]([OH:24])[C:2]#[C:1][C:3]2[CH:8]=[C:7]([C:9]3[S:10][CH:11]=[CH:12][CH:13]=3)[C:6]([O:14][CH3:15])=[CH:5][C:4]=2[O:16][CH3:17])=[CH:26][CH:27]=1Ex-1C: A solution of 2-(5-ethynyl-2,4-dimethoxy-phenyl)-thiophene (1.5 g, 6.14 mmol) from Ex-1B in THF (20 mL) was cooled to −78° C. n-Butyllithium (6.72 mmol, 4.2 mL of a 1.6 M solution in hexanes) was added dropwise while maintaining an internal temperature below −65° C. After aging for 30 min at −78° C., the reaction was transferred via cannula over 10 min to a cold (−78° C.) solution of methyl 4-formylbenzoate (1.07 g, 6.52 mmol) in THF (10 mL). The resulting solution was slowly warmed to 0° C. and then quenched with a saturated NH4Cl solution. The layers were separated, and the aqueous layer was extracted with ethyl acetate. The combined organic phases were dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Silica gel chromatography (hexane/ethyl acetate, 3:1, 1:1) gave 2.2 g (88%) of the desired 4-[3-(2,4-dimethoxy-5-thiophen-2-yl-phenyl)-1-hydroxy-prop-2-ynyl]-benzoic acid methyl ester as a greenish yellow solid, m.p. 128–130° C. 1H-NMR (300 MHz, CDCl3) d 8.08 (d, 2H, J=8.3 Hz), 7.75 (d, 2H, J=8.3 Hz), 7.68 (s, 1H), 7.37 (dd, 1H, J=3.6 and 1.7 Hz), 7.28 (dd, 1H, J=5.1 and 1.7 Hz), 7.06 (dd, 1H, J=5.1 and 3.6 Hz), 5.79 (d, 1H, J=6.6 Hz), 3.96 (s, 3H), 3.94 (s, 3H), 3.93 (s, 3H), 2.53 (d, 1H, J=6.6 Hz).
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