Br[C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[O:11][CH3:12].[Zn](CC)[CH2:14][CH3:15]>O1CCOCC1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.Cl[Pd]Cl.[Fe+2]>[CH2:14]([C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[O:11][CH3:12])[CH3:15]A mixture of 4-bromo-3-methoxy-benzoic acid (2.49 g, 10.9 mmol) and Pd(dppf)Cl2 (158 mg, 0.216 mmol) were stirred in dioxane (25 mL) and Et2Zn (22 mL, 1M in hexanes, 22 mmol) was added. The reaction mixture was heated at 70° C. for 1 h. The mixture was cooled to room temperature and was quenched with MeOH (1.1 mL). The solution was diluted with ethyl acetate (20 mL) and was washed with 1N HCl (10 mL). The combined organics were washed with brine, dried over sodium sulfate and evaporated to dryness to give 4-ethyl-3-methoxybenzoic acid. ESI-MS m/z calc. 180.1. found 179.1 (M−1)−; Retention time: 1.77 minutes (3 min run).
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