反应详情

温度

60 °C

tert-Butyl 2-methylspiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate (1.0 g, 3.27 mmol), potassium carbonate (497.7 mg, 3.60 mmol) and trifluoromethanesulfonate; 5-(trifluoromethyl)dibenzothiophen-5-ium (1.32 g, 3.27 mmol) were combined in acetonitrile (10 mL). The reaction mixture was heated at 60° C. for 16 h. The reaction was evaporated to dryness and the residue was dissolved in dichloromethane. The organics were washed with water and brine, dried over sodium sulfate and evaporated. The crude material was purified by silica gel chromatography eluting with 0-50% ethyl acetate in hexanes to give tert-butyl 2-methyl-6-(trifluoromethyl)spiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate (812 mg, 66%). ESI-MS m/z calc. 373.2, found 374.5 (M+1)+; Retention time: 1.21 minutes (3 min run). 1H NMR (400 MHz, CDCl3) δ 6.52 (d, J=3.8 Hz, 1H), 5.91 (d, J=3.8 Hz, 1H), 3.98 (t, J=6.0 Hz, 2H), 3.93-3.76 (m, 2H), 3.32 (t, J=6.0 Hz, 2H), 3.26-3.08 (m, 2H), 2.36 (s, 3H), 2.11-1.99 (m, 2H), 1.81-1.65 (m, 2H), 1.47 (s, 9H).

1. customThe reaction was evaporated to dryness
2. dissolutionthe residue was dissolved in dichloromethane
3. washThe organics were washed with water and brine
4. dry with materialdried over sodium sulfate
5. customevaporated
6. customThe crude material was purified by silica gel chromatography
7. washeluting with 0-50% ethyl acetate in hexanes