N-Fluorobenzenesulfonimide → Methyl [2-(2,2-dimethylpropyl)benzoxazol-5-yl]fluoroacetate

Participants

Reaction Conditions

Reaction Steps

A solution of lithium diisopropylamide (2.0M solution in tetrahydrofuran/ethylbenzene/heptane, 3.85 ml, 0.0077 mol) was added dropwise to a solution of methyl [2-(2,2-diethylpropyl)benzoxazol-5-yl]acetate (2.0 g, 0.0077 mol) in tetrahydrofuran (40 ml) at −78° C. under a nitrogen atmosphere and the mixture was stirred at −78° C. for 1 hour. A solution of N-fluorobenzenesulfonimide (2.42 g, 0.0077 mol) in tetrahydrofuran (10 ml) was added dropwise and the mixture was stirred at −70° C. for a further 1 hour. The cooling bath was removed and the mixture allowed to warm to room temperature over a period of 20 hours. The reaction mixture was diluted with water, acidified with dilute aqueous hydrochloric acid and extracted with ethyl acetate. The organic extracts were combined, washed with water, dried over anhydrous magnesium sulfate, filtered and the filtrate was evaporated in vacuo. The residue was purified by flash column chromatography on silica gel, eluting with ethyl acetate:dichloromethane 5:95, and was further purified by column chromatography on silica gel, eluting with ethyl acetate:hexane 1:3, to give methyl [2-(2,2-dimethylpropyl)benzoxazol-5-yl]fluoroacetate (1.4 g).

Provenance & Evidence