Reaction Steps
A THF (1 mL) solution of 44 (22.9 mg, 42.0 μmol, 1 equiv.) was cooled to −78° C. in a 10-mL test tube, and chlorotrimethylsilane (53 μL, 0.42 mmol, 10 equiv.) and a freshly prepared THF solution of lithium tetramethylpiperidide (0.50 M, 420 μL, 0.21 mmol, 5 equiv.) were sequentially added. The golden yellow solution was slowly warmed to 0° C. over 1 h and quenched at 0° C. with saturated aqueous NaHCO3. 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 a yellow oil. Flash column chromatography (20 mL SiO2, 98:2 hexane:EtOAc) afforded 23.4 mg (37.9 μmol, 90% yield) of 45 as a colorless oil. TLC Rf 0.40 (95:5 hexane:EtOAc). 1H NMR (600 MHz; CDCl3): δ 5.02-4.97 (m, 2H), 3.83 (s, 3H), 3.11 (s, 1H), 2.51 (dd, J=14.4, 6.3 Hz, 1H), 2.37 (dd, J=14.5, 7.5 Hz, 1H), 2.15-2.11 (m, 1H), 1.99 (dd, J=14.0, 3.7 Hz, 1H), 1.69 (s, 3H), 1.68-1.63 (m, 9H), 1.57 (s, 3H), 1.48 (td, J=12.7, 3.9 Hz, 1H), 1.46-1.37 (m, 2H), 1.30 (td, J=12.2, 4.1 Hz, 1H), 1.26-1.24 (m, 1H), 1.21 (s, 3H), 1.21 (s, 3H), 1.14 (td, J=12.6, 4.2 Hz, 1H), 0.94 (t, J=7.9 Hz, 9H), 0.80 (s, 3H), 0.57 (q, J=8.1 Hz, 6H), 0.23 (s, 9H). 13C NMR (126 MHz; CDCl3): δ 207.9, 198.6, 185.7, 133.70, 133.59, 127.7, 122.8, 120.0, 73.7, 72.6, 64.1, 59.7, 46.7, 45.7, 41.8, 39.29, 39.27, 30.6, 30.0, 29.7, 27.6, 26.02, 25.97, 18.21, 18.14, 17.88, 17.83, 7.4, 7.0, 0.8. HRMS-ESI (m/z): [M+H]+ calculated for C36H64O4Si2, 617.4416. found, 617.4395.
