Synthesis
Synthesis of Intermediate 1: 30.27 g (110.8 mmol) of 9,9-dimethyl-2-bromofluorene, 16.9 g (66.5 mmol) of iodine (I2) and 15.2 g (66.5 mmol) of periodate (H5IO6) were dissolved in acetic acid (AcOH). To this solution, dilute aqueous sulfuric acid (H2SO4) was slowly added dropwise and the reaction was stirred at 50°C for 5 hours. Upon completion of the reaction, deionized water was added to the reaction mixture and a solid precipitate was precipitated. The precipitate was collected by filtration to give 37.6 g of intermediate 1 in 85% yield. The resulting compound was structurally confirmed by high resolution mass spectrometry (HR-MS).
References
[1] Angewandte Chemie - International Edition, 2016, vol. 55, # 44, p. 13724 - 13728
[2] Angew. Chem., 2016, vol. 128, p. 13928 - 13932,5
[3] Patent: EP2292603, 2011, A1. Location in patent: Page/Page column 24
[4] Patent: EP2738166, 2014, A1. Location in patent: Paragraph 0153-0154
[5] Patent: EP2762478, 2014, A1. Location in patent: Paragraph 0179; 0180
