Compound 12

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Compound data: 1H NMR

Compound data: 13C NMR

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

To a 10 mL round-bottomed flask containing phomactin R (2) (15.0 mg, 0.0499 mmol) and NaHCO₃ (21.0 mg, 0.250 mmol) was added CH₂Cl₂ (1.5 mL) and cooled to 0 °C. m-CPBA (70%, 18.5 mg, 0.0749 mmol) was then added and the reaction mixture was allowed to stir at 0 °C. After 30 min, the reaction mixture was quenched with sat. NaHCO₃ aq. (1.0 mL) then warmed to room temperature. The mixture was diluted with CH₂Cl₂ (3.0 mL) and the phases were separated. The aqueous phase was extracted with CH₂Cl₂ (3.0 mL × 3). The combined organic layers were washed with brine (2.0 mL), dried over MgSO₄, filtered and concentrated under reduced pressure. The crude residue was purified by column chromatography (SiO₂, 10% to 30% EtOAc/ hexanes) to provide phomactin P (12) (10.5 mg, 66%) as a white solid. R_f: 0.27 (25% EtOAc/ hexanes); Melting Point: 175–178 °C; Optical Rotation: [α]²²_D = +99 (c 0.14, MeOH); ¹H NMR (600 MHz, CDCl₃): δ 5.94 (s, 1H), 5.18 (s, 2H), 3.86 (s, 1H), 2.86 (dd, J = 11.0, 3.8 Hz, 1H), 2.69 (ddd, J = 20.7, 6.2, 2.8 Hz, 1H), 2.25 (dt, J = 13.0, 3.7 Hz, 1H), 2.12 (tt, J = 14.1, 4.2 Hz, 1H), 2.04–1.99 (m, 1H), 1.95 (dd, J = 20.7, 5.0 Hz, 1H), 1.68–1.63 (m, 2H), 1.47 (dddd, J = 14.1, 11.0, 4.5, 3.2 Hz, 1H), 1.27 (s, 3H), 1.26 (s, 3H), 1.20 (dd, J = 14.9, 7.0 Hz, 1H), 1.11–1.04 (m, 2H), 1.02 (s, 3H), 0.82 (d, J = 7.0 Hz, 3H); ¹³C NMR (151 MHz, CDCl₃): δ 199.5, 144.2, 141.7, 131.2, 116.4, 64.5, 62.8, 59.3, 55.7, 42.2, 37.6, 35.6, 31.4, 29.1, 26.8, 24.3, 21.1, 19.1, 17.0, 13.6; HRMS (EI): Calculated for C₂₀H₂₈O₃ [M]⁺: 316.2038, found: 316.2029.