Compound 13

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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 2 mL vial containing a solution phomactin P (12) (4.4 mg, 0.014 mmol) and Rh₂(cap)₄ (1.4 mg, 0.0021 mmol) in CH₂Cl₂ (0.15 mL) was added TBHP (5.0 M solution in decane, 0.028 mL, 0.14 mmol) and the resulting mixture was heated to 40 °C and held at this temperature. After 4 h, the vessel was cooled to room temperature, then DBU (0.10 mL, 0.70 mmol) was added. After an additional 1 h of stirring, the solution was concentrated and purified by column chromatography (SiO₂, 10% to 30% EtOAc/ hexanes) to provide phomactin K (13) (2.4 mg, 52%) as a white solid. R_f: 0.23 (25% EtOAc/ hexanes); Melting Point: 172–174 °C; Optical Rotation: [α]²²_D = +135 (c 0.210, MeOH); ¹H NMR (600 MHz, CDCl₃): δ 5.82 (s, 1H), 5.63 (s, 1H), 5.57 (d, J = 1.4 Hz, 1H), 3.78 (s, 1H), 2.70 (dd, J = 10.8, 4.0 Hz, 1H), 2.30–2.26 (m, 2H), 2.18–2.07 (m, 2H), 1.53–1.45 (m, 2H), 1.30 (s, 3H), 1.26 (s, 3H), 1.28–1.23 (m, 1H), 1.18–1.14 (m, 1H), 1.12–1.07 (m, 1H), 1.01 (d, J = 7.4 Hz, 3H); ¹³C NMR (151 MHz, CDCl₃): δ 202.2, 197.5, 153.3, 143.3, 123.5, 123.4, 64.6, 63.6, 58.5, 55.3, 54.2, 46.2, 35.5, 29.8, 29.0, 24.3, 21.0, 18.9, 13.9, 13.5; HRMS (EI): Calc’d for C₂₀H₂₆O₄ [M]⁺: 330.1831, found: 330.1826.