13.16. Preparation of 9,9-Bis-(2-bromo-allyl)-9H-fluorene-d8 (74)

To a suspension solution of fluorene-d₈ (0.5 g, 2.85 mmol) in toluene (15 mL) under an argon atmosphere at room temperature, sodium hydroxide 50% solution (15 mL) was added, then 2,3-dibromopropene (1.0 mL, 8.55 mmol) was added to the reaction mixture. Tetra-butyl ammonium bromide (100 mg) was added as a phase-transfer catalyst. The reaction mixture was stirred overnight at room temperature. The work-up was carried out by adding ethyl acetate (15 mL) and separating the organic layer. The aqueous layer was washed with ethyl acetate (2 × 15 mL). The combined organic extracts were washed with dilute hydrochloric acid (5%, 15 mL) and water, dried over magnesium sulfate, and evaporated under reduced pressure. The oily crude product was purified by column chromatography on silica gel using a 98:2 mixture of hexanes/ethyl acetate as eluent to produce 74. Yield: 0.53 g (44%); ¹H NMR (CDCl₃) δ 3.24 (s, 2H), 4.89 (d, 1H), 5.12 (d, 1H,); ¹³C NMR (CDCl₃) δ 49.95, 54.89, 120.99, 126.88, 141.03, 148.53.