Compound 9

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Compound data: 1H NMR

Compound data: 13C NMR

Compound data: 19F NMR

Compound data: Crystallographic data

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

In a 15-mL scintillation vial, a mixture of 2c (47.2 mg, 20 µmol) and cis-3-hexene (100 mg, 1.2 mmol, distilled from calcium hydride and stored over 3Å molecular sieves) was chilled for 1 hour in a glovebox coldwell cooled with dry ice/acetone bath. A pre-cooled solution of KHMDS (6.0 mg, 30 µmol) in MTBE (2.0 mL) was added, and the mixture was stirred with cooling for 30 minutes. ¹³C NMR analysis of the crude mixture suggested the formation of a single major product (judging from quaternary carbon signals alpha to the nitrogen atom. See Supplementary Figure 43.). Then, the resulting mixture was passed through a glass filter, and evaporated to dryness. The solid residue was analysed by quantitative ¹H NMR using 1,3,5-trimethoxybenzene as an internal standard, and the NMR yield of 9 was determined to be 88% (See Supplementary Figure 44.). The absence of the trans-isomer 10 was confirmed by ¹⁹F NMR analysis of the same mixture (See Supplementary Figure 45.), which supports that 3c reacts as a singlet species in a concerted manner. The same reaction was repeated, and the obtained solid residue was recrystallized from chloroform/hexane (vapour diffusion) at room temperature, to afford 9 as colourless crystals suitable for X-ray crystallographic analysis. The crystals were grounded and dried in vacuo at 120 °C overnight, to afford 9 as a colourless powder (22.5 mg, 10 µmol, 51% yield). ¹H NMR (300 MHz, CDCl₃) δ 7.80 (s, 8H), 7.72 (s, 16H), 7.68 (s, 4H), 7.61 (s, 8H), 7.41 (m, 2H), 7.22 (dd, J = 5.8, 3.2 Hz, 2H), 2.10 (NCH, br s, 1H), 1.30–1.18 (CH₂CH₃, m, 2H), 0.90 (CHCH₂CH₃, m, 4H), 0.51 (CH₂CH₃, t, J = 7.0 Hz, 6H); ¹³C NMR (201 MHz, CDCl₃) δ 146.8 (4C, 4°), 144.7 (2C, 4°), 141.7 (8C, 4°), 139.2 (8C, 4°), 132.6 (q, ²J_C-F = 33.3 Hz, 16C, 4°), 129.4 (2C, 3°), 128.9 (8C, 3°), 126.8 (16C, 3°), 125.4 (4C, 3°), 124.7 (2C, 3°), 123.1 (q, ¹J_C-F = 273 Hz, 16C, 4°), 122.0 (8C, 3°), 81.4 (2C, 4°), 41.3 (1C, NCHR₂), 27.0 (2C, 3°), 20.6 (2C, 2°), 13.6 (2C, 1°); ¹⁹F NMR (282 MHz, CDCl₃) δ −63.1; HRMS (m/z): [M+TFA−H]⁻ calcd. for C₁₀₃H₅₃F₄₈N·CF₃CO₂, 2328.3267; found, 2328.3235.