反应详情

To tert-butyl 2-methylspiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate (10.0 g, 32.7 mmol) in DMSO (164 mL) was added ferrous sulfate heptahydrate (9.8 mL of 1.0 M, 9.8 mmol) followed by CF3I (6.41 g, 32.7 mmol) by slow bubbling through the solution and taking the weight difference of the canister. The mixture was cooled with a ice-water bath before H2O2 (3.71 mL of 30% w/v, 32.7 mmol) dropwise over 15 min keeping the internal temperature<20° C. The mixture was poured onto 300 mL of ice water and was extracted with EtOAc (2×400 mL). The combined organic phases were washed with brine, dried over MgSO4, filtered and concentrated in vacuo. The crude material was purified column chromatography eluting with 0-10% methanol in dichloromethane with 2% iPr2NEt to give tert-butyl 2-methyl-6-(trifluoromethyl)spiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate (7.8 g, 64%).

1. customby slow bubbling through the solution
2. customthe internal temperature<20° C
3. extractionwas extracted with EtOAc (2×400 mL)
4. washThe combined organic phases were washed with brine
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe crude material was purified column chromatography
9. washeluting with 0-10% methanol in dichloromethane with 2% iPr2NEt