反应详情

温度

-78 °C

A THF (1 mL) solution of 26 (16 mg, 41 μmol, 1 equiv.) was cooled to −78° C. in a 10-mL recovery flask, and chlorotrimethylsilane (0.21 mL, 1.6 mmol, 40 equiv.) and a freshly prepared THF solution of lithium diisopropylamide (0.50 M, 1.6 mL, 0.82 mmol, 20 equiv.) were added sequentially. The resulting yellow solution was stirred at −78° C. for 45 min and then allowed to warm to room temperature over 3.5 h. The golden yellow solution was then quenched at −20° C. with saturated aqueous NaHCO3 and extracted thrice with EtOAc. The organic extracts were combined, washed with H2O and brine, dried over Na2SO4, filtered, and concentrated in vacuo to a yellow oil. Flash column chromatography (30 mL SiO2, 95:5 to 8:2 hexane:EtOAc) afforded 10.7 mg (23.2 μmol, 57% yield) of 28 as a colorless oil along with 3.9 mg (10 μmol, 24% recovery) of 26. TLC Rf 0.62 (8:2 hexane:EtOAc). 1H NMR (600 MHz; C6D6): δ 5.54 (t, J=7.1 Hz, 1H), 5.47 (t, J=7.2 Hz, 1H), 3.37 (s, 3H), 2.99 (s, 3H), 2.97 (s, 3H), 2.77-2.71 (m, 2H), 2.42 (dd, J=15.0, 7.0 Hz, 1H), 2.41-2.34 (m, 1H), 2.06 (dd, J=13.3, 6.6 Hz, 1H), 1.84 (td, J=12.3, 5.2 Hz, 1H), 1.74 (s, 3H), 1.73-1.68 (m, 4H), 1.68 (m, 4H), 1.62 (s, 3H), 1.54 (s, 3H), 0.84 (t, J=7.0 Hz, 1H), 0.48 (s, 9H). 13C NMR (126 MHz; C6D6): δ 198.9, 184.3, 131.1, 130.9, 129.2, 125.5, 123.1, 110.0, 74.1, 64.0, 53.5, 52.3, 51.0, 50.6, 41.8, 38.0, 31.7, 28.2, 26.6, 25.92, 25.87, 17.82, 17.80, 16.4, 0.9. HRMS-ESI (m/z): [M+H]+ calculated for C27H44O4Si, 461.3082. found, 461.3094.

1. temperatureto warm to room temperature over 3.5 h
2. customThe golden yellow solution was then quenched at −20° C. with saturated aqueous NaHCO3
3. extractionextracted thrice with EtOAc
4. washwashed with H2O and brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo to a yellow oil