[CH2:1]([O:3][C:4](=[O:19])[CH:5]=[C:6]([O:8][C:9]1[C:18]2[CH2:17][CH2:16][CH2:15][CH2:14][C:13]=2[CH:12]=[CH:11][CH:10]=1)[CH3:7])[CH3:2].[Br:20]N1C(=O)CCC1=O>ClCCl.N(C(C)(CC(C)C)C#N)=NC(C)(CC(C)C)C#N>[CH2:1]([O:3][C:4](=[O:19])[CH:5]=[C:6]([O:8][C:9]1[C:18]2[CH2:17][CH2:16][CH2:15][CH2:14][C:13]=2[CH:12]=[CH:11][CH:10]=1)[CH2:7][Br:20])[CH3:2]A solution of 3-(5,6,7,8-tetrahydro-naphthalen-1-yloxy)-but-2-enoic acid ethyl ester (0.69 g, 2.65 mmol) in dichloromethane (14 mL) was treated with N-bromosuccinimide (0.50 g, 2.80 mmol) and 2,2′-azobis(2,4-dimethylvaleronitrile) (31.6 mg, 0.12 mmol). The reaction was then warmed to 45° C. where it stirred overnight. At this time, the reaction was diluted with dichloromethane (50 mL) and was washed with water (1×50 mL) and a saturated aqueous sodium chloride solution (1×50 mL), dried over magnesium sulfate, filtered, rinsed with dichloromethane, and concentrated in vacuo. Purification by Analogix flash chromatography (40 g, 1-10% ethyl acetate/hexanes) afforded impure 4-bromo-3-(5,6,7,8-tetrahydro-naphthalen-1-yloxy)-but-2-enoic acid ethyl ester (638.8 mg, 71%) as a yellow oil. The material was used without further purification.
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