Reacción #556122

Ecuación de reacción

2-chloro-4-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine

1,3-bis(dicyclohexylphosphino)propane bis(tetrafluoroborate)

potassium carbonate

methanol

→

title compound

Rendimiento 64.1%

Methyl 4-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)picolinate

Rendimiento 64.1%

Disolventes

ethyl acetate

DMF

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrowas evacuated
2. 2
   workup.ADDITIONfilled with nitrogen (3×)
3. 3
   Otroevacuated
4. 4
   workup.ADDITIONfilled with carbon monoxide (2×)
5. 5
   OtroThe cooled reaction
6. 6
   Filtraciónfiltered over Celite
7. 7
   Concentraciónconcentrated in vacuo
8. 8
   Otroto provide a dark red residue that
9. 9
   Filtraciónwas filtered through a silica plug
10. 10
    Lavadoeluting with ethyl acetate (60 mL)
11. 11
    ConcentraciónThe pale yellow eluent was concentrated in vacuo

Procedimiento

A mixture of 2-chloro-4-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (500 mg, 1.97 mmol), 1,3-bis(dicyclohexylphosphino)propane bis(tetrafluoroborate) (125 mg, 0.20 mmol), palladium(II) acetate (22 mg, 0.10 mmol), potassium carbonate (413 mg, 2.96 mmol), and methanol (1.20 mL, 29.59 mmol) in DMF (6 mL) was evacuated and then filled with nitrogen (3×), and then evacuated and filled with carbon monoxide (2×). The reaction mixture was then heated at 100° C. for 2 hours under a balloon of carbon monoxide. The cooled reaction was diluted with ethyl acetate (10 mL), filtered over Celite, and concentrated in vacuo to provide a dark red residue that was filtered through a silica plug, eluting with ethyl acetate (60 mL). The pale yellow eluent was concentrated in vacuo to afford the title compound as a yellow oil (350 mg, 64%). 1H NMR (400 MHz, CDCl3) δ 8.92 (s, 1H), 7.91 (s, 1H), 4.00 (s, 3H), 2.59 (s, 3H), 1.36 (s, 12H).

Fuente