Compound A1-2

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Compound data: Crystallographic data

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

In a glovebox, a solution of palladium complex {4,7-dit-Bu(t-Bu-Xantphos)Pd^IICF₃}(OCOCF₃) (B1-2) (0.1 mmol, 90 mg, 1.0 equiv) in degassed anhydrous THF (4.0 mL) was added dropwisely to a suspended solution of KC₈ (0.2 mmol, 27.0 mg, 2.0 equiv) in degassed anhydrous THF (3.0 mL) under -78 ^oC from a syringe. After stirring for 3 h under 0 ^oC, the resulting mixture was filtered by anhydrous Celite quickly. The filtrate was evaporated below 10 ^oC and the residue was washed several times by cold degassed anhydrous pentane to provide red powder, the palladium difluorocarbene complex {[4,7-dit-Bu(t-Bu-Xantphos)]Pd⁰=CF₂} (A1-2) (54 mg, 70% yield). ¹H NMR (400 MHz, THF-d₈) δ 7.74 (s, 2 H), 7.50 (s, 2 H), 1.59 (s, 6 H), 1.60 (s, 6 H), 1.40 (d, J = 13.1 Hz, 36H), 1.35 (s, 18 H). ¹³C NMR (126 MHz, THF-d₈) δ 231.0 (tt, J = 519.5, 67.6 Hz, Pd=CF₂), 157.8 (m), 144.3, 136.26 (d, J = 2.5 Hz), 136.24 (d, J = 2.5 Hz), 130.6, 122.7, 121.1, 37.6, 35.90 (d, J = 3.7 Hz), 35.87 (d, J = 3.7 Hz) 35.1, 31.7, 31.4 (m), 26.5.¹⁹F NMR (376 MHz, THF-d₈) δ 80.9 (t, J = 50.4 Hz, 2 F). ³¹P NMR (162 MHz, THF-d₈) δ 46.8 (t, J = 50.4 Hz, 2 P). Sample for the X-ray crystal structure analysis was recrystallized from pentane under -35 ^oC in glovebox. The crystal contains small amount of trifluoromethylpalladium complex.