[Br-].[C:2]([CH2:5][CH2:6][CH2:7][CH2:8][CH2:9][P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([OH:4])=[O:3].[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[CH3:39][O:40][C:41]1[CH:42]=[C:43]([CH:46]=[CH:47][CH:48]=1)[CH:44]=O.Cl>O1CCCC1>[CH3:39][O:40][C:41]1[CH:42]=[C:43]([CH:44]=[CH:9][CH2:8][CH2:7][CH2:6][CH2:5][C:2]([OH:4])=[O:3])[CH:46]=[CH:47][CH:48]=1
A solution was formed by adding (5-carboxypentyl)triphenylphosphonium bromide (1.67 g, 3.67 mmol), under an atmosphere of argon, to a 1 M solution of LiHMDS (in tetrahydrofuran) (7.34 mL, 7.34 mmol). The resultant dark red solution was allowed to stir at ambient temperature for 30 minutes. Commercially available 3-methoxybenzaldehyde (0.100 g, 0.734 mmol) was dissolved in 5 mL anhydrous tetrahydrofuran and subsequently added to the reaction solution. Stirring continued for 6 hours until 6 N hydrochloric acid was carefully added to quench the reaction solution to a pH 2. Ethyl acetate was added and the organic layer was separated. The aqueous phase was washed thrice with ethyl acetate. The combined organic layers were washed once with brine and dried over sodium sulfate. The solvent was removed in vacuo and the olefin acid product was purified as a off-white oily solid in 99% yield (0.170 g) as a 85E:15Z mixture of isomers using flash column chromatography (silica) (25% ethyl acetate:hexanes mobile phase): 1H NMR (500 MHz, CDCl3) δ 7.29-7.36 (m, 1H), 7.03 (d, J=7.5 Hz, 1H), 6.95-6.98 (m, 1H), 6.85-6.91 (m, 1H), 6.49 (d, J=11.5 Hz, 0.15H), 6.45 (d, J=15.5 Hz, 0.85H), 6.27-6.32 (m, 0.85H), 5.71-5.76 (m, 0.15H), 3.90 (s, 3H), 2.44-2.50 (m, 2.4H), 2.31-2.35 (m, 1.6H), 1.77-1.82 (m, 2H), 1.60-1.66 (m, 2H); 13C NMR (125 MHz, CDCl3) δ 180.65, 160.21, 139.62, 139.42, 132.95, 130.98, 130.62, 129.88, 129.64, 129.55, 121.72, 119.09, 114.77, 113.01, 112.50, 111.74, 55.61, 34.37, 33.00, 29.70, 29.11, 28.69, 24.73, 24.64.
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