Reaction #417942

Reaction equation

bis(pinacolato)diboron

potassium acetate

bromide

3,4-diamino-benzoic acid ethyl ester

→

2

4-methoxycarbonylphenylboronic acid

Solvents

dioxane

ethyl acetate

Conditions

Workup

1. 1
   WashThe organic phase was washed with H2O (20 mL)
2. 2
   Dryingdried over sodium sulfate
3. 3
   Concentrationconcentrated in vacuo
4. 4
   OtherThe residue was further purified by silica gel column chromatography (haxanes/ethyl acetate=1/4 to 0/1 (v/v))

Procedure

Referring to Scheme 11-1, to a solution of the bromide 1 (2.0 g, 4.2 mmol, prepared according to published conditions) in dioxane (60 mL) was added bis(pinacolato)diboron (4.32 g, 17 mmol), Pd(PPh3)4 (0.49 g, 0.42 mmol) and potassium acetate (2.06 g, 21 mmol) under nitrogen atmosphere. The reaction mixture was stirred at 80° C. for 5 h, and then diluted with ethyl acetate (150 mL). The organic phase was washed with H2O (20 mL), dried over sodium sulfate and concentrated in vacuo. The residue was further purified by silica gel column chromatography (haxanes/ethyl acetate=1/4 to 0/1 (v/v)) to give 2 (1.73 g, 79% yield). LC-MS (ESI): m/z 523.3 (M+H)+.

Source