Br[C:2]1[C:7]([CH3:8])=[C:6]([Cl:9])[CH:5]=[CH:4][N:3]=1.[CH:10]1([CH:13]=[O:14])[CH2:12][CH2:11]1.O>C1COCC1>[Cl:9][C:6]1[CH:5]=[CH:4][N:3]=[C:2]([CH:13]([CH:10]2[CH2:12][CH2:11]2)[OH:14])[C:7]=1[CH3:8]A solution of 2-bromo-4-chloro-3-methylpyridine (7 g, 28.1 mmol) in dry THF (150 mL) was cooled down to 0° C. An isopropyl magnesium chloride-Lithium chloride complex (26 mL, 33.8 mmol) was added carefully so temperature would not rise above 5° C. during the addition. The mixture was allowed to warm up to room temperature and was stirred for 1 h. The reaction mixture was cooled down to 0° C. and cyclopropane carboxaldehyde (2.5 mL, 33.5 mmol) was added carefully so temperature would not rise above 5° C. during the addition. The mixture was allowed to warm up to room temperature and was stirred for 1 h. The reaction mixture was cooled to 0° C. and water (150 mL) was added carefully so temperature would not rise above 10° C. during the addition. The mixture was allowed to warm up to room temperature and was stirred for 1 h. The mixture was extracted with ethyl acetate (3×100 mL). The combined organic phases were washed with brine (100 mL), dried over sodium sulfate and evaporated. The residue was purified by flash chromatography over silica gel (0-30% ethyl acetate in heptane) yielding a yellow oil (3.47 g, 16.8%).
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