Compound A5
(1'S,2'R,7'R,9'S,11'S,12'S,16'S,18'S)-2',16'-Dimethyl-18'-phenyldispiro[1,3-dioxolane-2,5'-[8]oxapentacyclo[9.7.0.02,7.07,9.012,16]octadecane-15',2''-[1,3]dioxolane]-18'-ol
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InChIKey IRJHPHFFPHMHIX-PYEWTQAYSA-N
Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.
m-Chloroperoxybenzoic acid (112 mg, 0.449 mmol calculated at 77% purity, dissolved in 1 mL of anhydrous dichloromethane) was added at room temperature to stirring solution of A9 (258.6 mg, 0.203 mmol) in anhydrous dichloromethane (2.6 mL). The reaction continued to stir for 40 minutes before a saturated solution of sodium bicarbonate was added to quench the reaction. The reaction contents were then extracted three times with dichloromethane. The combined organic layers were then washed once more with a saturated solution of sodium bicarbonate. The organic layer was then collected, dried with magnesium sulfate and concentrated to give a crude mixture. The epoxide diastereomers were then separated via column chromatography using 5:1 to 1:1 hexanes/ethyl acetate to afford 206.1 mg of A5 (77% yield) as a white solid and 60.1 mg of A15 (22% yield) as a white solid. M.p. 272-274 °C. 1H NMR (CDCl3, 500 MHz): δ 7.52 (m, 1H), 7.32 (m, 1H), 7.28 (m, 2H), 7.15 (t, J = 7.3 Hz, 1H), 3.90 - 3.71 (m, 6H), 3.70 - 3.60 (m, 2H), 2.76 (d, J = 3.7 Hz, 1H), 2.38 (d, J = 10.5 Hz, 1H), 2.33 (d, J = 14.0 Hz, 1H), 2.14 - 1.95 (m, 4H), 1.84 - 1.68 (m, 3H), 1.66 - 1.56 (m, 2H), 1.47 (s, 1H), 1.41 (s, 3H), 1.36 -1.32 (m, 2H), 1.22 (d, J = 14.6 Hz, 1H), 1.14 - 1.08 (m, 1H), 1.12 (s, 3H), 1.04 (dd, J = 14.5, 3.0, 1H), 0.79 (td, J = 13.9, 4.2 Hz, 1H). 13C NMR (CDCl3, 125 MHz): δ 153.0, 128.2, 128.0, 126.6, 125.9, 123.1, 119.4, 108.3, 79.7, 66.0, 65.2, 64.6, 64.6, 64.1, 57.0, 53.1, 51.5, 48.2, 45.4, 39.1, 38.2, 34.2, 33.2, 31.1, 29.3, 29.0, 23.3, 18.7, 16.0. HRMS(ESI): m/z calc. for C29H39O6 [M+H]+: 483.2747, found: 483.2746.
