[CH3:1][C:2]1[CH:6]=[C:5]([CH2:7][C:8]([O:10][CH2:11][CH3:12])=[O:9])[O:4][N:3]=1.Br[CH2:14][CH2:15]Br.[OH-].[Na+]>C1(C)C=CC=CC=1.O>[CH3:1][C:2]1[CH:6]=[C:5]([C:7]2([C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH2:15][CH2:14]2)[O:4][N:3]=1To a solution of ethyl 2-(3-methylisoxazol-5-yl)acetate (8.22 g, 48.6 mmol) in toluene (85 mL) was sequentially added n-tetrabutylammonium bromide (1.67 g, 5.18 mmol), 1,2-dibromoethane (7.0 mL, 81 mmol), and NaOH (30 mL, 582 mmol, ˜19.4 M). The reaction mixture was vigorously stirred at room temperature. After 1 h, the reaction mixture was cooled to 0° C. and diluted with water (50 mL). The aqueous phase was extracted with MTBE (3×). The combined organic phases were washed 1 N HCl, water (2×), dried over Na2SO4, and concentrated to give the product ethyl 1-(3-methylisoxazol-5-yl)cyclopropanecarboxylate (9.49 g, 48.6 mmol, 100% yield) as a clear oil. LC/MS m/z 196 [M+H]+.
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