反应详情

温度

-78 °C

A DCM (63 mL) solution of 30 (4.91 g, 12.5 mmol, 1 equiv.) and 2,6-lutidine (3.0 mL, 37.5 mmol, 3 equiv.) was cooled to −78° C. in a 200-mL round-bottom flask, and trimethylsilyl trifluoromethanesulfonate (4.5 mL, 25.0 mmol, 2 equiv.) was added slowly. The resulting bright yellow solution was stirred at −78° C. for 45 min and subsequently quenched at −78° C. with saturated aqueous NaHCO3. After warming the mixture to room temperature, it was extracted thrice with DCM. The organic extracts were combined, washed successively with 1 N HCl, H2O, and brine, dried over Na2SO4, filtered, and concentrated in vacuo to a faint yellow oil. Flash column chromatography (300 mL SiO2, 95:5 to 9:1 hexane:EtOAc) afforded 3.74 g (9.52 mmol, 77% yield) of 31 as a faint yellow oil. TLC Rf 0.49 (8:2 hexane:EtOAc). 1H NMR (600 MHz; CDCl3): δ 5.33 (t, J=7.1 Hz, 1H), 4.51 (dd, J=5.5, 2.1 Hz, 1H), 3.74 (d, J=4.6 Hz, 1H), 3.47 (s, 3H), 3.45 (s, 3H), 3.15 (s, 3H), 2.34 (dd, J=14.7, 6.9 Hz, 1H), 2.21 (dd, J=6.8, 1.8 Hz, 1H), 2.18 (dd, J=6.7, 2.3 Hz, 1H), 2.03 (m, 1H), 2.02-1.99 (m, 1H), 1.77 (dd, J=12.0, 4.6 Hz, 1H), 1.75 (d, J=12.0 Hz, 1H), 1.69 (s, 3H), 1.60 (s, 3H), 1.42-1.28 (m, 4H), 1.18 (td, J=12.6, 3.0 Hz, 1H), 1.12 (s, 3H), 1.11 (s, 3H), 1.11 (s, 3H), 1.03-0.95 (m, 1H). 13C NMR (126 MHz; CDCl3): δ 158.6, 131.2, 123.5, 112.6, 90.5, 79.0, 74.6, 54.5, 51.4, 49.3, 46.5, 44.5, 41.9, 41.2, 39.3, 34.0, 32.8, 28.2, 26.4, 25.22, 25.14, 20.1, 18.4, 18.0. FTIR (thin film) νmax: 2968, 2839, 1670, 1451, 1374, 1363, 1208, 1166, 1078, 1006, 843, 805, 785 cm−1. HRMS-ESI (m/z): [M+Na]+ calculated for C24H40O4, 415.2819. found, 415.2832.

1. customsubsequently quenched at −78° C. with saturated aqueous NaHCO3
2. temperatureAfter warming the mixture to room temperature
3. extractionit was extracted thrice with DCM
4. washwashed successively with 1 N HCl, H2O, and brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo to a faint yellow oil