[Br:1][C:2]1[CH:14]=[CH:13][C:12]2[C:11]3[C:6](=[CH:7][C:8](Br)=[CH:9][CH:10]=3)[C:5]([CH3:17])([CH3:16])[C:4]=2[CH:3]=1.B(OC(C)C)(OC(C)C)[O:19]C(C)C.C([Li])CCC.Cl>C1COCC1.CCCCCC>[Br:1][C:2]1[CH:3]=[C:4]2[C:12]([C:11]3[CH:10]=[CH:9][C:8]([OH:19])=[CH:7][C:6]=3[C:5]2([CH3:17])[CH3:16])=[CH:13][CH:14]=1
21.2 g (58.6 mmol) of 2,7-dibromo-9,9-dimethyl-9H-fluorene (CAS No. 28320-32-3) and 19.0 ml (82.8 mmol) of triisopropyl borate are dissolved in 500 ml of THF, and 56 ml (89 mmol) of a 15 percent solution of n-butyllithium in n-hexane are added at −70° C. After 2 h, 200 ml of 2 M hydrochloric acid are added, and the batch is allowed to thaw at room temp. and extracted three times with MTB ether. The combined org. phases are dried over sodium sulfate, the solvent is removed in vacuo, and the residue is taken up in 400 ml of toluene. After addition of 85 ml of 2 M sodium hydroxide solution, 15.5 ml of 30 percent hydrogen peroxide are added with vigorous stirring at such a rate that the temp. does not exceed 40° C. When the addition is complete, the batch is stirred for a further 30 min, added to 500 ml of water and acidified using 2 M hydrochloric acid. The aqueous phase is separated off and extracted three times with ethyl acetate. The combined org. phases are washed with dil. ammonium iron(II) sulfate soln. and water, dried over sodium sulfate and evaporated. Filtration of the crude product through silica gel with toluene/ethyl acetate (9:1) gives 7-bromo-9,9-dimethyl-9H-fluoren-2-ol as colourless solid.
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