Sodium hydride → N-tert-butoxycarbonyl-4-[5-fluoro-1-(2-trimethylsilylethanesulfonyl)indol-3-yl]piperidine

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Reaction Steps

Sodium hydride (96 mg, 4.07 mmol) was added to a solution of N-tert-butoxycarbonyl-4-(5-fluoroindol-3-yl)piperidine (1.28 g, 4.07 mmol), [prepared as described in Step 1, above] in DMF (6 ml) at 0° C. and the reaction mixture was stirred for 30 min. 2-Trimethylsilylethanesulfonyl chloride (820 mg, 4.07 mmol) was added and the reaction mixture was slowly warmed to RT over 30 min. After 2.5 h, the reaction mixture was quenched with water (10 ml) and the product was extracted into methylene chloride. The combined organic layers were dried over MgSO4 and concentrated in vacuo. Due to incomplete reaction the above steps were repeated on the isolated crude reaction mixture. The final residue was chromatographed (PTLC, SiO2, 20% ethyl acetate/hexanes) to afford N-tert-butoxycarbonyl-4-[5-fluoro-1-(2-trimethylsilylethanesulfonyl)indol-3-yl]piperidine (84%) as a clear oil.

Provenance & Evidence