[CH3:1][O:2][C:3](=[O:21])[C:4]1[CH:9]=[CH:8][C:7](OS(C2C=CC(C)=CC=2)(=O)=O)=[CH:6][CH:5]=1.C1COCC1.CN1CCCC1=O.[CH2:34]([Mg]Br)[CH2:35][CH2:36][CH2:37][CH2:38][CH3:39]>CCOCC>[CH3:1][O:2][C:3](=[O:21])[C:4]1[CH:5]=[CH:6][C:7]([CH2:34][CH2:35][CH2:36][CH2:37][CH2:38][CH3:39])=[CH:8][CH:9]=1A flame-dried two-necked flask is charged under argon with 4-(4-methylbenzenesulfonyloxy)benzoic acid methyl ester (0.50 g, 1.63 mmol), Fe(acac)3 (29 mg, 0.08 mmol), THF (10 mL) and N-methylpyrrolidone (NMP, 0.95 mL). A solution of n-hexylmagnesium bromide (2M in Et2O, 1 mL, 2 mmol) is added via syringe to the resulting red solution, causing an immediate color change to dark brown and finally to violet. The resulting mixture is stirred for 5 min, the reaction is diluted with Et2O and is carefully quenched upon addition of aq. HCl (1M, ca. 10 mL). Work-up followed by flash chromatography of the crude product as described above provides 4-hexylbenzoic acid methyl ester as a colorless syrup (298 mg, 83%). The spectroscopic and analytical data are identical to those compiled above.
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