m-Chloroperbenzoic acid → (S)-tert-butyl 4-((1-fluorocyclohexyl)methyl)-2,2-dimethyloxazolidine-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

(S)-tert-Butyl 4-((1-hydroxycyclohexyl)methyl)-2,2-dimethyloxazolidine-3-carboxylate (2.70 g, 8.63 mmol) was dissolved in CH2Cl2 and the solution was cooled to −78° C. DAST (2.78 g, 17.2 mmol, 2.0 equiv) was added via syringe and the solution was stirred overnight with concomitant warming to rt. LC-MS showed consumption of the starting alcohol. Satd aq NaHCO3 was added and the mixture was stirred for 1 h. The layers were separated and the organic layer was washed with brine, dried over Na2SO4, and filtered. The resulting solution was treated with m-CPBA (1.5 g, 8.6 mmol) and stirred for 3 h. After this time the olefinic by-products from the fluorination were consumed. The excess m-CPBA was quenched by addition of 10% aq Na2S2O3 (50 mL). The layers were separated and the organic layer was washed with satd aq NaHCO3 and brine, dried over Na2SO4, filtered and evaporated. Flash chromatography on silica, eluting with 0-29% EtOAc in hexanes, afforded (S)-tert-butyl 4-((1-fluorocyclohexyl)methyl)-2,2-dimethyloxazolidine-3-carboxylate (725 mg).

Provenance & Evidence