2,2,2-Trifluoroethyl trifluoromethanesulfonate → 9-Tert-butyl 2-methyl 4-(2,2,2-trifluoroethyl)-1-oxa-4,9-diazaspiro[5.5]undecane-2,9-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

2,2,2-Trifluoroethyl trifluoromethanesulfonate (164 μL, 1.06 mmol) was added to a solution of 9-tert-butyl 2-methyl 1-oxa-4,9-diazaspiro[5.5]undecane-2,9-dicarboxylate (222 mg, 0.71 mmol) and NaHCO3 (237 mg, 2.83 mmol) in anhydrous EtOH (6 mL) at room temperature. The reaction mixture was purged with argon, sealed with a cap and heated at 70° C. for 12 hours. The reaction mixture was cooled to room temperature, filtered and concentrated in vacuo. The crude material was purified by silica gel column chromatography using 0 to 30% EtOAc in DCM as eluent to yield 9-tert-butyl 2-methyl 4-(2,2,2-trifluoroethyl)-1-oxa-4,9-diazaspiro[5.5]undecane-2,9-dicarboxylate (197 mg, 68%). ESI-MS m/z calc. 410.4. found 411.5 (M+1)+; Retention time: 2.08 minutes (3 min run).

Provenance & Evidence