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To a solution of <strong>[99365-48-7]4-bromoindolin-2-one</strong> (500 mg, 2.358 mmol) in THF (8 mL) was added slowly a 1M solution of LiHMDS in THF (5.188 ml, 5.188 mmol) via syringe at -78 C under nitrogen. The reaction mixture was stirred at that temperature for 30 min, then 1,3-diiodopropane (0.354 ml, 3.065 mmol) was added. The reaction mixture was warmed slowly to room temperature and stirred overnight. It was quenched with saturated aqueous NH4C1, then extracted with ethyl acetate. The combined organics were concentrated, the residue was purified by silica gel column chromatography with 25% ethyl acetate hexanes. The combined solvent was concentrated to give the title compound (265 mg) with 85 % purity. LCMS m/z = 252.2 [M+H]+.
20 mg
To a stirred solution of <strong>[99365-48-7]4-bromoindolin-2-one</strong> (200 mg, 0.943 mmol) in THF (15 mL) was added dropwise n-butyllithium solution 2.5M in hexane (1.3 mL) at 0C. The resulting solution was stirred at 0C for 30min. Tetramethylethylenediamine (383.6 mg, 3.3 mmol) and l,3-diiodopropane (251 mg, 0.849 mmol) were added. The solution was slowly warmed up to room temperature and stirred overnight. The reaction was concentrated. The residue was treated with MeOH and solid was filtered off. The filtrate was concentrated and purified by prep-TLC (EtOAc / Hexanes = 1 / 1) to get 4'-bromospiro[cyclobutane-l,3'-indolin]-2'-one (20 mg).