Br[C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[CH:4][C:3]=1[Cl:9].C1(P(C2C=CC=CC=2)CCCP(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(N(CC)CC)C.[CH3:46][OH:47].CN(C)[CH:50]=[O:51]>C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[Cl:9][C:3]1[CH:4]=[C:5]([CH3:8])[CH:6]=[CH:7][C:2]=1[C:46]([O:51][CH3:50])=[O:47]To 4-bromo-3-chlorotoluene (4.97 g, 24.2 mmol) in dimethylformamide (25 mL) is added palladium acetate (0.54 g, 2.42 mmol), 1,3-bis(diphenylphosphino)propane (0.998 g, 2.42 mmol), triethylamine (12.5 mL) and methanol (12.5 mL). The reaction vessel is evacuated and purged three times with carbon monoxide gas. A balloon filled with carbon monoxide gas is used to maintain the carbon monoxide atmosphere. The reaction mixture is heated at 80° C. for 8 hr. The mixture is washed with water and extracted with hexanes (2×50 mL). The combined organic layers are dried over sodium sulfate, filtered, concentrated, and chromatographed with 0–3% ethyl acetate in hexanes. 1.24 g (28%) of methyl 2-chloro-4-methylbenzoate is isolated as a colorless oil.
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