[CH3:1][C@H:2]1[CH2:7][NH:6][C@H:5]([CH3:8])[CH2:4][N:3]1[C:9]([O:11][CH2:12][CH3:13])=[O:10].[CH2:14](Br)[CH:15]=[CH2:16].C(=O)([O-])[O-].[Na+].[Na+]>C(#N)C>[CH2:16]([N:6]1[C@H:5]([CH3:8])[CH2:4][N:3]([C:9]([O:11][CH2:12][CH3:13])=[O:10])[C@@H:2]([CH3:1])[CH2:7]1)[CH:15]=[CH2:14]A mixture of ethyl trans-2,5-dimethyl-1-piperazinecarboxylate (643 g, 3.45 mol), allyl bromide (328 mL, 3.80 mol), and sodium carbonate (440 g, 4.15 mol) in 2500 mL of acetonitrile was heated at reflux for 1.5 hours. The reaction was cooled to room temperature, filtered, and the solvent removed under vacuum. The residue was dissolved in 4000 mL of dichloromethane and washed with two 500 mL portions of 1 M sodium hydroxide. The dichloromethane solution was dried over magnesium sulfate and the solvent was removed to give 630 g (81%) of ethyl trans-4-allyl-2,5-dimethyl-1-piperazinecarboxylate as an oil.
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