C(NC(C)C)(C)C.[CH2:8]([Li])[CH2:9][CH2:10][CH3:11].[CH3:13][O:14][C:15](=[O:25])[CH2:16][N:17]=[CH:18][C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1.BrCCC=C.CN(C)P(N(C)C)(N(C)C)=O>O1CCCC1.CCCCCC.O>[CH3:13][O:14][C:15](=[O:25])[CH:16]([CH2:11][CH2:10][CH:9]=[CH2:8])[N:17]=[CH:18][C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1Dissolve diisopropylamine (15.4 mL, 110 mmol) in tetrahydrofuran (250 mL), place under a nitrogen atmosphere and cool to -78° C. Add n-butyllithium (39 mL of a 2.7M solution in hexane, 105 mmol). Stir for 30 minutes and add, by dropwise addition, a solution of N-(phenylmethylene)glycine methyl ester (17.7 g, 100 mmol) in tetrahydrofuran (25 mL). Stir for 15 minutes and add 4-bromobutene (13.5 g, 100 mmol) and allow to warm slowly to room temperature. Add hexamethylphosphoramide (20 mL, 100 mmol) and stir under a nitrogen atmosphere for 3 hours. Pour into water, extract into ethyl ether and wash with brine several times. Dry (MgSO4) and evaporate the solvent in vacuo to give the title compound as an amber oil (25 g).
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