Triphenylphosphine → 3-chloro-8-((S)-2,2-dimethyl-[1,3]dioxolan-4-yl methoxy)-4-fluoro-6,6-dimethyl-5,6-dihydro-benzo[b]carbazol-11-one

Participants

Reaction Conditions

Reaction Steps

3-Chloro-4-fluoro-8-hydroxy-6,6-dimethyl-5,6-dihydro-benzo[b]carbazol-11-one (Compound S2-3, 20.0 mg, 0.061 mmol) was dissolved in THF (0.25 mL), added with ((S)-2,2-dimethyl-[1,3]dioxolan-4-yl)-methanol (9.8 μL, 0.079 mmol), triphenylphosphine (20.7 mg, 0.079 mmol) and diethyl azodicarboxylic acid (35.9 μl, 0.079 mmol), and then stirred at 40° C. for 5 hr. The reaction solution was concentrated under reduced pressure, and the resulting residues were purified by silica gel column chromatography (ethyl acetate/hexane) to obtain the intermediate, 3-chloro-8-((S)-2,2-dimethyl-[1,3]dioxolan-4-yl methoxy)-4-fluoro-6,6-dimethyl-5,6-dihydro-benzo[b]carbazol-11-one. This compound was dissolved in THF (0.10 mL) and MeOH (0.08 ml), added with sulfuric acid (0.5 M, 0.045 ml), and then stirred at 60° C. for 1 hr. The reaction solution was added with saturated aqueous solution of sodium hydrogen carbonate, extracted with ethyl acetate and dried over anhydrous magnesium sulfate. The yellow solid obtained after concentration under reduced pressure was washed with methylene chloride/hexane solvent and filtered to obtain the title compound (4.3 mg, 18%).

Provenance & Evidence