Triisopropyl borate → [4-(Pyrrolidine-1-sulfonyl)phenyl]boronic acid

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (20 mL, 31 mmol) was added dropwise over 30 min to a cooled (−78° C.) solution of 1-[(4-bromobenzenesulfonyl)pyrrolidine (3.0 g, 10.3 mmol) and triisopropyl borate (7.2 mL, 30.9 mol) in anhydrous tetrahydrofuran (10 mL) under a nitrogen atmosphere. The reaction mixture was stirred for 1 h at −78° C. whereafter the temperature was allowed to reach room temperature over 3 h. Silica gel was added and the solvent was evaporated. Chromatography on a silica gel column using a gradient methylene chloride (100%) to methylene chloride/ethanol, (1:1), gave 1.85 g (70% yield) of the title compound as a white solid: 1H NMR (CD3OD, 400 MHz) δ 7.90 (d, J=7 Hz, 2H), 7.75 (d, J=8 Hz, 2H), 3.21 (m, 4H), 1.72 (m, 4H); 13C NMR (CDCl3/CD3OD (1:1), 100 MHz) δ 136.79, 133.50, 125.48, 47.19, 24.30; MS (ES) m/z 256 (M++1).

Provenance & Evidence