Reaction #155929

Reaction equation

Na2CO3

6-bromoindazole

4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester

K2CO3

→

4-(1H-indazol-6-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester

Solvents

1,4-dioxane

Conditions

Workup

1. 1
   Temperaturecooled to room temperature
2. 2
   ExtractionThe resulting mixture was extracted with EtOAc (3×)
3. 3
   WashThe combined extracts were washed with brine
4. 4
   Dryingdried over Na2SO4
5. 5
   FiltrationThe resulting mixture was filtered
6. 6
   Concentrationconcentrated under reduced pressure
7. 7
   Otherthe residue purified by flash chromatography on silica-gel (gradient eluent heptane to 60% EtOAc in heptane)

Procedure

To a mixture of 6-bromoindazole (2.0 g, 10.2 mmol), 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (3.5 g, 11.2 mmol) and Pd(PPh3)4 (1.2 g, 1.0 mmol) under N2 were added 1,4-dioxane (80 mL), followed by addition of K2CO3 (2 M in H2O, 20 mL, 40 mmol). The resulting mixture was heated at 110° C. for 16 h, then cooled to room temperature. The resulting mixture was then treated with saturated Na2CO3 aqueous solution. The resulting mixture was extracted with EtOAc (3×). The combined extracts were washed with brine and then dried over Na2SO4. The resulting mixture was filtered, concentrated under reduced pressure, and the residue purified by flash chromatography on silica-gel (gradient eluent heptane to 60% EtOAc in heptane) to yield 4-(1H-indazol-6-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester as brownish foam solid.

Source