Br[CH2:2][C:3]([O:5][CH2:6][CH3:7])=[O:4].[CH3:8][CH:9]([CH2:12][CH2:13][CH:14]=[C:15]([CH3:22])[CH2:16][CH2:17][CH:18]=[C:19]([CH3:21])[CH3:20])[CH:10]=[O:11].S(=O)(=O)(O)O>C1C=CC=CC=1.[Zn]>[CH3:8][CH:9]([CH2:12][CH2:13][CH:14]=[C:15]([CH3:22])[CH2:16][CH2:17][CH:18]=[C:19]([CH3:21])[CH3:20])[CH:10]([OH:11])[CH2:2][C:3]([O:5][CH2:6][CH3:7])=[O:4]A suspension of zinc (59 g) in benzene (400 ml) is heated up to the reflux temperature, and a mixture of ethyl bromoacetate (120 g) and 2,6,10-trimethyl-5,9-undecadienal (135 g) is added thereto. The resulting mixture is refluxed for 2 hours, cooled and poured into 5% aqueous solution of sulfuric acid. The benzene layer is washed with water, dried and evaporated. The residual material is distilled under reduced pressure to give ethyl 3,7,11-trimethyl-6,10-dodecadien-2-ol-1-carboxylate (100 g) as a pale yellow oil. B.P. 139° to 142°C/0.08 mm Hg. IR: 3480, 1030 cm-1 (OH); 1720, 1180cm-1 (COO). NMR (carbon tetrachloride): δ 1.25 (t), 1.58 (s), 1.65 (s), 1.95 (m), 2.38 (m), 4.10 (m), 5.05 (m).
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