Reaction #425501

Reaction equation

methyl 6-chloro-5-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)-1H-indole-3-carboxylate

4-bromoveratrole

potassium carbonate

water

→

title compound

Yield 84.0%

methyl 6-chloro-5-(3,4-dimethoxyphenyl)-1H-indole-3-carboxylate

Yield 84.0%

Solvents

toluene

ethanol

ethyl acetate

Conditions

Workup

1. 1
   Otherwas degassed with nitrogen for 5 minutes
2. 2
   TemperatureThe reaction was cooled to room temperature
3. 3
   OtherThe layers were separated
4. 4
   Extractionthe aqueous layer was back-extracted twice with ethyl acetate
5. 5
   DryingThe combined organic layers were dried over sodium sulfate
6. 6
   Filtrationfiltered
7. 7
   Concentrationconcentrated in vacuo

Procedure

A mixture of methyl 6-chloro-5-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)-1H-indole-3-carboxylate (100 mg, 0.31 mmol), 4-bromoveratrole (83 mg, 0.37 mmol), and aqueous potassium carbonate solution (2M, 0.62 mL, 1.24 mmol) in toluene (1.8 mL) and ethanol (0.6 mL) was degassed with nitrogen for 5 minutes then treated with [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (13.8 mg, 0.016 mmol). The reaction mixture was heated to 110° C. for 2.5 h. The reaction was cooled to room temperature and poured into water and ethyl acetate. The layers were separated and the aqueous layer was back-extracted twice with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash column chromatography was performed on the crude product using heptanes/ethyl acetate (4:1 to 1:1) to give the title compound (90 mg 84%). MS (ES+) 346.2 (M+H)+. 1H NMR (500 MHz, DMSO-d6) δ 12.05 (br. s., 1H), 8.17 (s, 1H), 7.94 (s, 1H), 7.64 (s, 1H), 7.04 (d, J=8.29 Hz, 1H), 6.98 (s, 1H), 6.93 (d, J=8.29 Hz, 1H), 3.81 (s, 3H), 3.79 (s, 3H), 3.78 (s, 3H).

Source