Boron trifluoride etherate → 2-[2-Azido-2-(3-bromo-phenyl)-propoxy]-3,3,3-trifluoro-2-methyl-propionic acid methyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of 2-[2-(3-bromo-phenyl)-2-hydroxy-propoxy]-3,3,3-trifluoro-2-methyl-propionic acid methyl ester (5.1 g, 11.92 mmol) in toluene (50 ml) was added trimethylsilyl azide (3.95 ml, 29.8 mmol) and at 0° C. BF3-Et2O (4.53 ml, 35.8 mmol). The reaction mixture was stirred for 2 days at 25° C. and for another day at 40° C. The reaction was carefully quenched by slow addition of the reaction mixture to a cold aqueous NH4OH solution. The product was extracted with EtOAc and the combined organic layers were washed with brine, dried over MgSO4, filtered and evaporated. The crude product was purified by flash-chromatography on silica gel (toluene to toluene/EtOAc 10:1) to provide a diastereomeric mixture of the title compound as a light yellow oil: TLC (toluene/EtOAc 10:1): Rf=0.69; HPLC RtH5=1.560 min; 1H NMR (360 MHz, CDCl3): δ 7.65 (s, 1H), 7.48 (d, 1H), 7.41 (d, 1H), 7.27 (t, 1H), 3.87 and 3.85 (s, 3H), 3.76 (m, 2H), 1.78 and 1.75 (s, 3H), 1.65 and 1.61 (s, 3H); ESIMS: 427, 429 [(M+NH4)+].

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