Benzene → 3,4-Dimethoxy-5-(prop-1-yn-1-yl)benzoic acid

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Reaction Steps

To a stirred solution of 3-iodo-4,5-dimethoxybenzoic acid (12.32 g, 40.0 mmol) in mixture of Et3N (80 mL) and benzene (80 mL) at room temperature was added CuI (760 mg, 4 mmol) followed by Pd(PPh3)4 (924 mg, 0.8 mmol, 0.02 eq.). After stirring for 2 days under propyne atmosphere (balloon) at room temperature, the solvent was removed, the residue was suspended in 1N HCl aqueous solution (300 mL) and then extracted with EtOAc (3×100 mL). The combined organic layer wash washed with brine (300 mL), dried over Na2SO4 and then concentrated in vacuo to give 3,4-dimethoxy-5-prop-1-ynylbenzoic acid (9.7 g). The product was used without further purification.

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