Boron tribromide → HCID 54302491, compound

Participants

Reaction Conditions

Reaction Steps

A solution of boron tribromide in CH2Cl2 (1.0 M, 250 mL, 250 mmol) was added dropwise over 30 min to a solution of methyl (S)-8-methoxy-3-oxo-2-(2,2,2-trifluoroethyl)-2,3,4,5-tetrahydro-1H-2-benzazepine-4-acetate (21.5 g, 62.3 mmol) in anhydrous CH2Cl2 (230 mL) at −20° C. under argon. After an additional 1.5 hr at −15 to −20° C., the reaction was recooled to −20° C. and quenched by careful dropwise addition of MeOH (250 mL). The reaction was stirred at −10 to 0° C. for 1 hr, then was concentrated on the rotavap. The residue was reconcentrated from MeOH (2×). Purification by flash chromatography on silica gel (50% ethyl acetate/hexanes) gave the title compound (19.38 g, 94%) as a white solid: [α]D −130.50 (c 1.0, MeOH); TLC (silica, 40% EtOAc/hexane) Rf 0.40; MS (ES) m/e 332.1 (M+H)+; 1H NMR (400, CDCl3+2% DMSO-d6) δ 6.92 (d, J=8.3 Hz, 1 H), 6.71 (dd, 1H), 6.58 (d, J=2.5 Hz, 1H), 5.29 (d, J=16.7 Hz, 1 H), 4.21-3.98 (m, 2H), 3.96 (d, J=16.7 Hz, 1H), 3.82 (m, 1H), 3.68 (s, 3H), 2.98 (dd, 1H), 2.94 (dd, 1H), 2.83 (dd, 1H), 2.46 (dd, 1H). Anal. Calcd for C15H16F3NO4: C, 54.38; H, 4.87; N, 4.23. Found: C, 54.40; H, 4.96; N, 4.22.

Provenance & Evidence