Reaction Steps
A THF (2 mL) solution of 40 (144 mg, 0.269 mmol, 1 equiv.) was cooled to −78° C. in a 25-mL recovery flask, and a freshly prepared THF solution of lithium tetramethylpiperidide (0.50 M, 2.2 mL, 1.1 mmol, 4 equiv.) was added. The resulting orange solution was stirred at −78° C. for 15 min and then stirred at 0° C. for 40 min. The reaction was then quenched with saturated aqueous NaHCO3 at 0° C. The mixture was warmed to room temperature and extracted thrice with EtOAc. The organic extracts were combined, washed with H2O and brine, dried over Na2SO4, filtered, and concentrated in vacuo to an orange oil. Flash column chromatography (75 mL SiO2, 7:3 hexane:EtOAc) afforded 104.3 mg (0.2117 mmol, 79% yield) of 41 as a faint yellow oil. TLC Rf 0.56 (1:1 hexane:EtOAc). 1H NMR (600 MHz; CDCl3): δ 5.63 (s, 1H), 4.95 (t, J=7.0 Hz, 1H), 3.78 (d, J=7.8 Hz, 1H), 3.73 (s, 3H), 3.15 (s, 1H), 2.47 (dd, J=14.5, 6.4 Hz, 1H), 2.37 (dd, J=14.5, 7.6 Hz, 1H), 2.09 (dd, J=13.4, 5.4 Hz, 1H), 1.88 (s, 1H), 1.73 (dd, J=13.3, 11.6 Hz, 1H), 1.65 (m, 7H), 1.52 (td, J=12.6, 3.5 Hz, 1H), 1.39 (td, J=12.5, 4.1 Hz, 1H), 1.34-1.27 (m, 2H), 1.23 (m, 4H), 1.18 (s, 3H), 0.92 (t, J=7.9 Hz, 9H), 0.86 (s, 3H), 0.54 (q, J=7.8 Hz, 6H). 13C NMR (126 MHz; CDCl3): δ 205.4, 193.1, 177.4, 134.4, 119.0, 105.9, 73.6, 72.0, 69.2, 57.0, 56.0, 46.2, 45.6, 39.4, 38.4, 30.6, 29.50, 29.48, 26.1, 18.1, 17.9, 15.7, 7.3, 6.9. HRMS-ESI (m/z): [M+Na]+ calculated for C28H48O5Si, 515.3163. found, 515.3170.
