Compound 17

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Compound data: CIF

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

17 was prepared from S29 following a literature procedure (US2010/179194 A1 filled 28 Mar 2008, issued 15 Jul 2010). Dess-Martin Periodinane (456 mg, 1.07 mmol, 2.5 equiv.) was added to a solution of S29 (188 mg, 0.43 mmol, 1.0 equiv.) in CH₂Cl₂(8 mL) at 0 ºC. The mixture was allowed to warm to 22 °C and stir for 3 h. A saturated solution of NH₄Cl was added and the aqueous layer was washed with EtOAc (3 x 5 mL). The combined organic layers were washed with brine, dried over Na₂SO₄ and concentrated in vacuo. The resulting pale yellow oil was purified by silica gel chromatography (8:1 hexanes:diethyl ether) to afford 17 (131.4 mg, 0.302 mmol, 56% overall yield for 3 steps) as colorless oil. IR (neat): 3444 (w, br), 2955 (w), 2927 (w), 1720 (m), 1677 (w), 1589 (m), 1435 (w), 1259 (s), 1166 (s), 1085 (s), 961 (w), 801 (m), 752 (s), 706 (m), 699 (m), 638 (m), 540 (w) cm^–1; ¹H NMR (400 MHz, CDCl₃): δ 8.01–7.98 (1H, m), 7.84–7.73 (2H, m), 7.49 (2H, d, J = 1.8 Hz), 7.35 (1H, t, J = 1.9 Hz), 5.63 (1H, s), 3.94 (3H, s), 3.86 (1H, d, J = 17.6 Hz), 3.69 (1H, d, J = 17.5 Hz), 2.66 (3H, s); ¹³C NMR (100 MHz, CDCl₃): δ 198.7, 166.9, 141.1, 140.8, 137.8, 135.3, 135.1, 131.1, 131.0, 129.1, 125.3, 125.1, 124.0 (q, J = 283.6 Hz), 75.9 (q, J = 29.6 Hz), 52.3, 40.5, 21.6; ¹⁹F NMR (376 MHz, CDCl₃): δ 72.91 (3F, s); HRMS Calcd for C₁₉H₁₆Cl₂F₃O₄ [M+H]⁺: 435.0378; Found: 435.0387. [α]^20.0_D = 109.90 (c = 1.30, CHCl₃) for a 95:5 er sample (based on er of 4r).