Reacción #3389

Ecuación de reacción

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

nBuLi

diisopropylamine

2,6-difluoropyridine

→

oil

Rendimiento 50.2%

7a-(2,6-difluoro-3-pyridinyl)-hexahydro-1H-pyrrolizine

Rendimiento 50.2%

Disolventes

—

hexanes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITwas continued for 1 hour at -78° C
3. 3
   Otrothe cold bath was removed
4. 4
   TemperaturaAfter warming to ambient temperature
5. 5
   workup.ADDITIONa solution of 2N HCl was added
6. 6
   Otrothe phases were separated
7. 7
   Extracciónextracted with CH2Cl2 (2×)
8. 8
   Secadodried (MgSO4)
9. 9
   Concentraciónconcentrated
10. 10
    Otrochromatographed (silica gel; CHCl3 /MeOH, 98:2)

Procedimiento

A solution of 2.5M nBuLi (675 μL, 1.7 mmol) in hexanes was added to diisopropylamine (220 μL, 1.6 mmol) in THF (4.5 mL) at ambient temperature. After 10 minutes of stirring, the reaction mixture was cooled to -78° C., 2,6-difluoropyridine (145 μL, 1.6 mmol) was introduced, and stirring was continued for 1 hour at -78° C. 1,2,3,5,6,7-hexahydropyrrolizinium perchlorate (500 mg, 2.4 mmol) was then added, and the cold bath was removed. After warming to ambient temperature, a solution of 2N HCl was added and the phases were separated after pouting the reaction mixture over EtOAc. The aqueous phase was basified with 15% NaOH solution and extracted with CH2Cl2 (2×). The CH2Cl2 extracts were combined, dried (MgSO4), concentrated and chromatographed (silica gel; CHCl3 /MeOH, 98:2) to afford a clear oil (180 mg, 50%). MS (CI/NH3) m/e: 225 (M+H)+. 1H NMR (CDCl3, 300 MHz) δ1.5-1.63 (m, 2H), 1.78-1.89 (m, 2H), 1.92-2.10 (m, 4H), 2.63-2.70 (m, 2H), 3.08-3.12 (m, 2H), 6.72 (dd, J=8.1, 3.0 Hz, 1H), 8.33 (dd, J=18.0, 8.1 Hz, 1H).

Fuente