[CH3:1][CH2:2][Mg+].[Br-].[Zn](CC)CC.Cl[C:11]1[CH:20]=[CH:19][C:14]([C:15]([O:17][CH3:18])=[O:16])=[CH:13][CH:12]=1>C1COCC1.CN1C(=O)CCC1.[O-]S([O-])(=O)=O.[Zn+2]>[CH3:18][O:17][C:15](=[O:16])[C:14]1[CH:19]=[CH:20][C:11]([CH2:2][CH3:1])=[CH:12][CH:13]=1
A solution of EtMgBr (3 M in Et2O, 0.9 mL) is added to a solution of Et2Zn (3 M in toluene, 1 mL) at −78° C. After stirring for 15 min, the resulting cold solution of the zincate is added dropwise to a solution of methyl 4-chlorobenzoate (354 mg, 2.10 mmol) and Fe(acac)3 (36 mg, 0.1 mmol) in THF (6 mL) and NMP (0.5 mL) at 0° C. causing a spontaneous color change from yellow to brown-black. Standard extractive work up followed by flash chromatography affords 4-ethylbenzoic acid methyl ester (93%) the analytical and spectroscopic data of which are identical to those of a commercial sample.
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