Potassium Carbonate → Tert-butyl 8-but-2-ynyl-10,10-difluoro-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a mixture of crude tert-butyl 10,10-difluoro-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (65.0 mg, 0.222 mmol) and K2CO3 (61.5 mg, 0.445 mmol) in N,N-dimethylformamide (1.0 mL) was added 1-bromobut-2-yne (29.2 μL, 0.334 mmol) and the reaction heated at 45° C. for 48 h. The reaction was diluted with ethyl acetate and filtered. The filtrate was dried over Na2SO4, filtered and concentrated. Silica gel chromatography (4 g silica, 1-100% ethyl acetate/hexane) provided tert-butyl 8-but-2-ynyl-10,10-difluoro-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (50.0 mg, 65%) as a colorless oil. ESI-MS m/z calc. 344.2. Found 345.3 (M+1)+; Retention time: 1.91 minutes (3 min run). 1H NMR (400 MHz, CDCl3) δ 3.80 (br s, 2H), 3.35 (q, J=2.2 Hz, 2H), 3.23 (t, J=12.1 Hz, 2H), 2.80 (t, J=8.5 Hz, 2H), 2.48 (s, 2H), 2.02 (d, J=13.2 Hz, 2H), 1.84 (t, J=2.3 Hz, 3H), 1.54-1.48 (m, 2H), 1.46 (s, 9H).

Provenance & Evidence