Synthesis
1. Bromobenzene (37.7 g, 0.24 mol) was mixed well with 200 mL of THF (tetrahydrofuran) in a pressure-equilibrium dropping funnel.
2. Add magnesium shavings (6.1 g, 0.25 mol) to a 1 L triple-necked flask protected by nitrogen and preheat at 55-60 °C.
3. 20 mL of the above bromobenzene/THF mixture was taken and slowly added dropwise to the reaction flask as an initiator for the Grignard reaction, maintaining the temperature at 55-60 °C for 0.5 h. The reaction was carried out for 0.5 h. The remaining bromobenzene/THF mixture was added to the reaction flask.
4. Add the remaining bromobenzene/THF mixture to the reaction system slowly dropwise, maintain the temperature at 55-60 °C and stir the reaction for 2 hours.
5. 9-Fluorenone (36.0 g, 0.20 mol) was dissolved in 100 mL of THF and slowly added dropwise to the above reaction system, the dropwise addition time was controlled to be 0.5 hours.
6. After the dropwise addition was completed, the reaction was continued at 55-60°C with stirring for 2 hours.
7. Upon completion of the reaction, add 200 mL of 2.5 mol/L aqueous ammonium chloride to the reaction system to quench the reaction.
8. After standing and layering, the organic phase was separated and washed with deionized water.
9. The solvent was removed by pressure-reduced distillation, and the crude product obtained was recrystallized with toluene or ethanol to obtain a light yellow solid 9-phenyl-9-fluorenol in 88% yield.
References
[1] Advanced Synthesis and Catalysis, 2016, vol. 358, # 6, p. 947 - 957
[2] Journal of Organic Chemistry, 2018, vol. 83, # 11, p. 6162 - 6170
[3] Patent: CN105541747, 2016, A. Location in patent: Paragraph 0041; 0042; 0043
[4] Patent: CN107337680, 2017, A. Location in patent: Paragraph 0046; 0047; 0048; 0049; 0054
[5] Patent: CN107573356, 2018, A. Location in patent: Paragraph 0061; 0063; 0064; 0065
