To a suspension of 2-(3-chloro-2-hydroxy-benzoylamino)-indan-2-carboxylic acid ethyl ester (14) (250 mg, 0.69 mmol), anhydrous Cs2CO3 (453 mg, 1.39 mmol), and KI (23 mg, 0.14 mmol) in DMF (10 mL) is added 3-bromo-propene (70 μL, 0.83 mmol). The resulting reaction suspension is stirred at RT overnight. After the removal of DMF in vacuo, the residue is dissolved in EtOAc (20 mL) and washed with water (1×5 mL) and brine (2×5 mL). The organic layer is dried over anhydrous Na2SO4 and concentrated in vacuo. The residue is purified by flash column chromatography (80 g silica gel, gradient elution: 10-40% EtOAc in heptane) to give a pure product (17) as white solid (160 mg, 58%).
