Synthesis
1. indole (11.7 g, 0.1 mol) and bromobenzene (117 mL) were added to a four-necked flask, stirred and heated to 150-160°C for reflux.
2. cuprous chloride (2.47 g, 0.025 mol), L-proline (5.75 g, 0.05 mol) and potassium hydroxide (11.22 g, 0.2 mol) were added sequentially and the reaction was carried out for 8-12 h. The progress of the reaction was monitored by TLC.
3. After completion of the reaction, it was slightly cooled, the reaction mixture was filtered, the brown solid was washed with water, and the insoluble material cuprous chloride was dried and recycled.
4. The organic layer of the filtrate is washed with water and the bromobenzene is subsequently recovered by vacuum distillation. 5.
5. Finally, 1-phenylindole (17.76 g, 92.02% yield) was purified by distillation under reduced pressure.
References
[1] Journal of Organic Chemistry, 2001, vol. 66, # 23, p. 7729 - 7737
[2] Tetrahedron Letters, 2000, vol. 41, # 4, p. 481 - 483
[3] Tetrahedron Letters, 2017, vol. 58, # 32, p. 3155 - 3159
[4] New Journal of Chemistry, 2018, vol. 42, # 4, p. 2782 - 2789
[5] Comptes Rendus Chimie, 2018, vol. 21, # 7, p. 659 - 668
