1-Benzylpiperazine → Ethyl 4-(4-benzylpiperazin-1-yl)benzofuran-2-carboxylate

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**Purpose:** Buchwald-Hartwig coupling using unpurified ethyl 4-bromobenzofuran-2-carboxylate. The analysis on crude 4-bromobenzofuran-2-carboxylate shows traces of non cyclized and non aromoatized by-products. 2010-03-10 16:38:11: To a 25 mL rounbottomed flask was added ethyl 4-bromobenzofuran-2-carboxylate (1 g; 3.72 mmol) and toluene (10 mL/g-bulk-LR; 10 mL). The mixture was concentrated under reduced pressure to remove traces of water. The procedure was repeated once more. and finally toluene (10 mL/g-bulk-LR; 10 mL). The system was inerted three times and stirred under nitrogen gas. 17:03:56: To the homogenous mixture was added 1-benzylpiperazine (1.3 eq; 0.852 g; 0.84 mL; 4.83 mmol), TRIS(DIBENZYLIDENEACETONE)DIPALLADIUM(0) (0.02 eq; 68 mg; 0.07 mmol), 2-(DI-T-BUTYLPHOSPHINO)BIPHENYL (0.06 eq; 67 mg; 0.22 mmol) and CESIUM CARBONATE (1.2 eq; 1.453 g; 4.46 mmol). The system was inerted three times and stirred under nitrogen gas. 17:07:37: The Tj was set to Tj=100 °C. The mixture was stirred under nitrogen gas over night. 2010-03-11 08:42:44: IPC1 (15 h) sample was gathered and diluted with methanol. The analysis (EN03690-35-001-A) showed only 16 % conversion. **Results and conclusion:** The experiment was discarded due to poor conversion.

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