Toluene → Methyl-N-tert-butyloxycarbonyl-amino-4,4'-biphenyl-R-alanine

Participants

Reaction Conditions

Reaction Steps

Nitrogen is passed through a suspension of (R)-2-(t-butoxycarbonyl-amino)-3-[4-(trifluoromethylsulfonyloxy)-phenyl]-propionate (1.75mmol), 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° C., 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 (R)-2-(t-butoxycarbonylamino)-3-(p-phenylphenyl)-propionate which can also be called N-(R)-t-butoxycarbonyl-(p-phenylphenyl)-alanine methyl ester.

Provenance & Evidence