Acetone → 3,3-Dimethyl-1,3-dihydro-2,1-benzoxaborol-1-ol

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-(2′-bromophenyl)-6-butyl[1,3,6,2]dioxazaborocan (93.1 g, 277.1 mmol) in THF (2.3 L) at −78° C. was added n-BuLi (133.0 mL, 2.5M in hexane, 332.5 mmol, 1.2 equiv.) dropwise via a syringe over a period of 10 min while maintaining reaction temperature at −78° C. After the addition the reaction solution was stirred for 20 min at −78° C. before acetone (23.2 mL, 387.9 mmol, 1.4 equiv.) was added dropwise via a syringe over a period of 10 min while maintaining the reaction temperature at −78° C. The resulting mixture was allowed to stir for 20 min at −78° C. then warm to room temperature gradually. Once the reaction vessel reached room temperature, 6N HCl solution (1 L) was added and the mixture was stirred for an additional 30 min. The mixture was extracted with EtOAc (3×). The EtOAc extracts were dried over Na2SO4, filtered and concentrated under reduced pressure. The light yellow oil was then subjected to flash chromatography (Isco Companion, 80 g SiO2 cartridge, solid loaded SiO2, neat heptanes to 20:80 EtOAc gradient at 60 ml/min for 90 min). The title compound was recovered as clear colorless oil. 1H NMR (400 MHz, DMSO-d6) δ ppm 1.44 (s, 6 H) 7.31 (d, J=1.1 Hz, 1 H) 7.38-7.47 (m, 2 H) 7.66 (d, J=7.2 Hz, 1 H) 8.99 (s, 1 H). Amount obtained: 16.9 g (37.7% yield).

Provenance & Evidence