C[C:2]([CH3:5])([O-:4])C.[K+].[Br:7][C:8]1[CH:13]=[CH:12][C:11]([O:14][CH3:15])=[CH:10][C:9]=1[CH:16]([CH3:20])C([O-])=O.[C:21](OCC)(=[O:27])[C:22]([O:24][CH2:25][CH3:26])=[O:23].O.C[CH2:33][O:34]CC>>[O:27]=[C:21]([CH:20]([C:33]([O:4][CH2:2][CH3:5])=[O:34])[CH2:16][C:9]1[CH:10]=[C:11]([O:14][CH3:15])[CH:12]=[CH:13][C:8]=1[Br:7])[C:22]([O:24][CH2:25][CH3:26])=[O:23]Potassium t-butoxide (6.72 g) was suspended in 30 ml of anhydrous ether and cooled to 0° C. A solution of 14.35 g of ethyl 3-(2-bromo-5-methoxyphenyl-propionate and 10.95 g diethyl oxalate in 10 ml ether was added dropwise over 15 min. After 2 at 25° C., the reaction was poured into 100 ml H2O and the aqueous layer was separated, acidified to pH 1 and extracted with ether. The ether layer was dried (MgSO4) and the solvent was evaporated to yield 17.48 g of the desired product as a colorless oil (90%). NMR (CDCl3) δ1.20 (t, 3H), 1.35 (t, 3H), 3.32 (dd, 2H), 3.76 (s, 3H), 4.18 (q, 2H), 4.32 (q, 2H), 4.53 (t, 1H), 6.67 (dd, 1H), 6.80 (d, 1H), 7.40 (d, 1H).
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