Potassium Carbonate → 2-tert-Butoxycarbonylamino-3-(4'-dibenzofuran-4-yl-biphen-4-ylsulfanyl)-propanoic acid methyl ester

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Reaction Steps

A solution of 2-tert-Butoxycarbonylamino-3-(4-bromophenylsulfanyl)-propanoic acid methyl ester (0.55 g, 1.41 mmol), 4-(4-dibenzofuranyl)benzeneboronic acid (0.44 g, 1.52 mmol) and Pd(PPh3)4 (0.073 g, 5 mol %) in toluene (15 mL) and ethanol (3.0 mL) was treated with 2 M K2CO3 (2.2 mL). The reaction mixture was heated to reflux for 2 h, cooled to room temperature, diluted with ethyl acetate (100 mL). The organic layer was washed successively with 2% aq HCl and sat. aq NaCl, dried over MgSO4 and concentrated. Purification by flash column chromatography (2-10% ethyl acetate in heptane) gave the desired product (552 mg, 72%) as a white solid. 1H NMR (CDCl3), δ 8.01 (d, J=6 Hz, 2 H), 7.96 (dd, J=4 Hz, 8 Hz, 2H), 7.74 (d, J=9 Hz, 2 H), 7.66 (m, 4 H), 7.42 (m, 5 H), 5.41 (d, J=7 Hz, 1 H), 4.62 (m, 1 H), 3.73 (s, 3 H), 3.45 (d, J=4 Hz, 2H), 1.57 (s, 9 H). LCMS 454 (M+−100).

Provenance & Evidence