Reaction #169405

Reaction equation

tri-t-butyl phosphine tetrafluoroborate

6-Bromo-1H-indazole

t-butylacetate

LiHMDS

→

title compound

Yield 65.2%

tert-Butyl 1H-indazol-6-ylacetate

Yield 65.2%

Solvents

toluene

Conditions

Workup

1. 1
   OtherThe mixture was quenched with water (10 mL)
2. 2
   Extractionthen extracted with EtOAc (3×25 mL)
3. 3
   WashThe combined organic phases were washed with water (2×10 mL), brine (10 mL)
4. 4
   Dryingdried over sodium sulphate (Na2SO4)
5. 5
   OtherThe filtrate was evaporated in vacuo
6. 6
   Otherpurified by column chromatography on silica gel (hexane:EtOAc 80:20)

Procedure

6-Bromo-1H-indazole (1.3 g, 6.6 mmol) and t-butylacetate (1.33 mL, 9.9 mmol) in toluene (20 mL) were degassed with argon for 15 mins. Then the mixture was cooled to 0° C. and LiHMDS (16.5 mL, 16.5 mmol, 1M in hexane) was added dropwise. Bis(dibenzylideneacetone)palladium (380 mg, 0.66 mmol) and tri-t-butyl phosphine tetrafluoroborate (383 mg, 1.32 mmol) were added and the mixture was stirred at 10° C. for 2 hours. The mixture was quenched with water (10 mL) then extracted with EtOAc (3×25 mL). The combined organic phases were washed with water (2×10 mL), brine (10 mL) and dried over sodium sulphate (Na2SO4). The filtrate was evaporated in vacuo and purified by column chromatography on silica gel (hexane:EtOAc 80:20) to afford the title compound as a white solid (65%, 1.00 g).

Source