Reacción #3409

Ecuación de reacción

3,5-dibromopyridine

t-BuLi

1,2,3,5,6,7-hexahydropyrrolizinium perchlorate

→

oil

Rendimiento 28.4%

7a-(5-bromo-3-pyridinyl)-hexahydro-1H-pyrrolizine

Rendimiento 28.4%

Disolventes

pentane

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturawarm to -10° C.
2. 2
   workup.STIRRINGstir for 2 hours
3. 3
   OtroThe cold bath was removed
4. 4
   workup.ADDITION2N HCl was added
5. 5
   Otrothe phases were separated
6. 6
   Extracciónextracted with CH2Cl2 (2×)
7. 7
   Secadodried (MgSO4)
8. 8
   Concentraciónconcentrated
9. 9
   Otrothe residue was chromatographed (silica gel; CHCl3 /MeOH, 98:2)

Procedimiento

3,5-dibromopyridine (500 mg, 2.11 mmol, Aldrich) was dissolved in Et2 O and cooled to -95° C. A solution of 2.5M t-BuLi (1.7M in pentane, 2.7 mL, 4.64 mmol) in pentane was added dropwise. 1,2,3,5,6,7-hexahydropyrrolizinium perchlorate (663 mg, 3.2 mmol) was added, and the reaction mixture was allowed to stir and warm to -10° C. and stir for 2 hours. The cold bath was removed, 2N HCl was added, and the phases were separated. The aqueous phase was basified with 15% NaOH and extracted with CH2Cl2 (2×). The CH2 Cl2 fractions were combined, dried (MgSO4) and concentrated, and the residue was chromatographed (silica gel; CHCl3 /MeOH, 98:2) to afford a clear oil (160 mg, 28%): 1H NMR (CDCl3, 300 MHz) 67 1.57-1.71 (m, 2H), 1.79-2.04 (m, 6H), 2.62-2.73 (m, 2H), 3.11-3.20 (m, 2H), 8.04 (dd, J=2.0, 2.0 Hz, 1H), 8.46 (d, J=2.0 Hz, 1H), 8.58 (d, J=2.0 Hz, 1H); MS (CI/NH3) m/z: 267/269 (M+H)+.

Fuente