Iodine → (S)-methyl 2-(benzyloxycarbonylamino)-3-(1H-indol-5-yl)propanoate

Beteiligte Stoffe

Reaktionsschritte

To a suspension of zinc (2.53 g, 38.8 mmol) in DMF (20 mL) was added I2 (1.10 g, 4.15 mol) followed by addition of a solution of (R)-methyl 2-(benzyloxycarbonylamino)-3-iodopropanoate (4.70 g, 13.0 mmol) in DMF (20 mL). The mixture was stirred at ambient temperature for 5 min and heated at 35° C. for 40 min. Then a solution of 5-bromo-1H-indole (3.00 g, 15.5 mmol) in DMF (10 mL), Pd2(dba)3 (0.25 g, 0.27 mmol) and S—Phos (0.25 g, 0.60 mmol) were added. The reaction mixture was stirred at 50° C. under nitrogen overnight and then cooled to ambient temperature. Brine (500 mL) was added and the resulting mixture was extracted with EtOAc (200 mL×3). The organics were combined, washed with brine (300 mL) and concentrated. The residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc=10:1 to 5:1) to afford (S)-methyl 2-(benzyloxycarbonylamino)-3-(1H-indol-5-yl)propanoate as a viscous oil (3.27 g, 60% yield).

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