Trifluoroacetic acid → Tert-butyl 8-(2,2-difluoropropyl)-10-(methoxymethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl 2-(methoxymethyl)-4-(2-oxopropyl)-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate in dichloromethane (1 mL) was added and N,N-diethylaminosulfur trifluoride (195 μL, 1.47 mmol). Cesium fluoride (9.0 mg, 0.059 mmol) was then added in two portions followed by trifluoroacetic acid (5 μL, 0.06 mmol). The reaction was stirred for 15 min then cooled to 0° C. and quenched with 5 mL of saturated aqueous NaHCO3. The reaction was diluted with dichloromethane (5 mL) and the layers separated. The organic layer was washed with water, dried over Na2SO4, filtered and concentrated in vacuo to provide tert-butyl 8-(2,2-difluoropropyl)-10-(methoxymethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate as yellow oil. ESI-MS m/z calc. 378.2. found 379.3 (M+1)+; Retention time: 1.53 minutes (3 min run).

Provenance & Evidence