p-Toluenesulfonic acid → Methyl 2-methyl-7-nitro-2,3-dihydrobenzofuran-4-carboxylate

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Reaction Steps

Methyl 2-allyl-3-hydroxy-4-nitro-benzoate 1d (800 mg, 3.30 mmol) was dissolved in 10 mL of 1,2-dichloroethane followed by the addition of 1 mL of p-toluenesulfonic acid. The reaction solution was stirred for 48 hours. The resulting solution was added with 10 mL of saturated sodium bicarbonate solution and extracted with dichloromethane (20 mL×3). The combined organic phase was washed with water (20 mL) and saturated sodium chloride solution (20 mL) successively, then dried over anhydrous magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound methyl 2-methyl-7-nitro-2,3-dihydrobenzofuran-4-carboxylate 30a (100 mg, yield: 12.5%) as a yellow solid.

Provenance & Evidence