CuBr·SMe2 (0.0013 g, 0.0060 mmol) was added to a 4 mL dry vial equipped with a stir bar. The vial was sealed with a rubber diaphragm. The sealed vial was then purged and filled three times with argon, followed by the addition of anhydrous THF (0.60 mL), phenylethynyl magnesium bromide (1.0 M in THF) (0.30 mL, 0.30 mmol), and (cyclohexylmethyl) magnesium bromide. Di-tert-butyldiazinone (1) (0.0562 g, 0.33 mmol) was then added to the stirred mixture. The reaction mixture was vigorously stirred at room temperature under argon for 3 hours, concentrated, and purified by rapid chromatography (silica gel, pentane). 4 g of the cross-coupled product was a colorless oil (0.0482 g, 81%). A white solid Decafluorobiphenyl (0.0477 g, 58%) was obtained.
Melting point 112-113°C (up to 116-118°C); IR (pure) 160714831249979 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.40-7.33 (m, 2H), 7.05-6.99 (m, 2AH), 3.87 (s, 3H); ¹⁹F NMR (282 MHz, CDCl₃) δ -143.7 (dd, JF=23.1, 7.9 Hz, 2F), -156.6 (t, JF=20.9 Hz, 2F). Hz, 1F), -162.6 (td, JF=23.1, 7.9 Hz, 2F; HRMS calculated value of C13H7F5O(M+): 274.0412; found: 274.0409.
Figure: Synthetic route of Decafluorobiphenyl
