Toluene → (S)-Methyl 3-([1,1'-biphenyl]-4-yl)-2-((tert-butoxycarbonyl)amino)propanoate

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Reaction Steps

Nitrogen is passed through a suspension of (S)-2-(t-butoxycarbonylamino)-3-[4-(trifluoromethylsulfonyloxy)-phenyl]-propionate (1.75 mmol), phenylboronic acid (3.5 mmol), anhydrous potassium carbonate (2.63 mmol) and toluene (17 mL) for 15 minutes. Tetrakis(triphenylphosphine)palladium(0) is added, and the mixture is heated at 85°-90° for 3 hours. The reaction mixture is cooled to 25°, diluted with ethyl acetate (17 mL) and washed sequentially with saturated sodium bicarbonate (1×20 mL), water (1×20 mL), 10% citric acid (1×20 mL), water (1×20 mL) and saturated sodium chloride solution (1×20 mL). The organic phase is concentrated, and the residue is purified by column chromatography (silica gel, hexane/ethyl acetate 2:1) to yield methyl (S)-2-(t-butoxycarbonylamino)-3-(4-biphenylyl)-propionate which can also be called N-(S)-t-butoxycarbonyl-(4-biphenyl)-alanine methyl ester, m.p. 83°-85°; [α]20D +54.81° (c=1, CHCl3).

Provenance & Evidence