Compound 1a

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InChIKey DKWAHGKLRRMFRD-UHFFFAOYSA-N

Compound data: CIF

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

To a stirring solution of I (0.88 g, 5 mmol) in 30 mL of dry acetonitrile under nitrogen was slowly added potassium tert-butoxide (K^tBuO) (0.57 g, 5.1 mmol). The reaction mixture was left stirring for 5 minutes, after which 1-Chloro-2-diphenylphosphinoethane (1.25 g, 5 mmol) was added and the reaction was left stirring for 12 hours at room temperature. All further manipulations were performed in the air. The solution was filtered through a fine fritted funnel filled with a layer of Celite™ and the solvent was removed under vacuum. The residue was chromatographed on silica column with dichloromethane/hexanes mixtures followed by recrystallization from cold pentane (-20 °C) to afford analytically pure 1a as crystalline white solid (1.79 g, 92%). ¹H NMR (400.1 MHz, CD₂Cl₂, 30 °C): δ 7.41-7.34 (m, 4H, ArH), 7.32-7.23 (m, 6H, ArH), 3.40-1.20 (bm, 9H, cage-BH), 2.95 (s, 2H, cage-CH), 2.56 (bm, 2H, SCH₂), 2.32 (m, 2H, PCH₂); ¹³C{¹H} NMR (100.6 MHz, CD₂Cl₂, 30 °C): δ 138.8 (d, ArC, J_C-P= 14 Hz), 133.4 (d, ArC, J_C-P= 19 Hz), 129.2 (s, ArC), 129.0 (d, ArC, J_C-P= 7 Hz), 54.9 (s, cage-CH), 31.3 (d, AliphC, J_C-P= 15 Hz), 29.9 (d, AliphC, J_C-P= 24 Hz); ¹¹B (128.4 MHz, CD₂Cl₂, 30 ^oC, BF₃-Et₂O): δ – 0.7 (s, 1B, B-S), -7.7 (d, ¹J_B-H= 164 Hz, 2BH), -11.0 (d, ¹J_B-H= 155 Hz, 1BH), -14.2 (d, ¹J_B-H= 104 Hz, 2BH), -15.0 (d, ¹J_B-H= 111 Hz, 2BH), -18.5 (d, ¹J_B-H= 181 Hz, 1BH), -21.5 (d, ¹J_B-H= 184 Hz, 1BH); ³¹P{¹H} NMR (162.0 MHz, CD₂Cl₂, 30 °C): δ - 16.3 (s). Calculated for C₁₆H₂₅B₁₀PS: C, 49.46; H, 6.49; found: C, 49.80; H, 6.48. Single crystals suitable for X-ray diffraction studies were grown by slow evaporation from n-pentane in a NMR tube. Ligands 1c, 1d, 1e, and 1f were synthesised and isolated by an analogous method, replacing I with the corresponding thiol precursor.