A solution of 4-hydroxyindole (266 mg, 2 mmol) in acetone (20 mL) was cooled to 0° C. under nitrogen and anhydrous potassium carbonate (414 mg, 3 mmol) was added. A solution of commercial diethyl bromomalonate (92%; 520 mg, 2 mmol) in acetone (20 mL) was added dropwise. After stirring for 5 h at room temperature, more diethyl bromomalonate (92%; 520 mg) was added and the mixture was stirred at room temperature overnight. Work up and flash chromatography as above afforded 7 (360 mg, 45%) and 8 (123 mg, 21%).
