Chlorotrimethylsilane → (3S,4aR,4bS,6S,8R,8aR,10aR)-3-Furan-3-yl-4a,8a-dimethyl-1,5-dioxo-6-trimethylsilanyloxy-dodecahydro-2-oxa-phenanthrene-8-carboxylic acid methyl ester

Beteiligte Stoffe

Reaktionsschritte

A solution of 8a (0.08 g, 0.20 mmol), NEt3 (0.1 mL, 0.72 mmol) and chlorotrimethylsilane (0.1 mL, 0.79 mmol) in CH2Cl2 (30 mL) was stirred at room temperature overnight. The mixture was washed with saturated NaHCO3 (2×10 mL) and H20 (50 mL), dried (Na2SO4), and the solvent was removed under reduced pressure. The resulting crude solid was purified by column chromatography (eluent: ethyl acetate/nhexanes) to afford 16 (0.06 g, 68%) as a white solid, mp 197-200° C.; 1H NMR (CDCl3): δ 0.14 (9H, s, (CH3)3SiO; 1.11 (3H, s, H-19); 1.48 (3H, s, H-29); 1.50-1.73 (3H, m, H-7α,β and H-11β); 1.79 (1H, ddd, J=3.0, 3.0, 10.5 Hz, H-6α); 2.03 (1H, dd, obscured, H-8); 2.06 (1H, s, H-10); 2.10-2.38 (3H, m, H-3α,β and H-6β); 2.57 (1H, dd, J=5.1, 10.5 Hz, H-11α); 2.69 (1H, dd, J=3.9, 12.9 Hz, H-4); 3.72 (3H, s, CO2CH3); 4.12 (1H, dd, J=7.5, 11.7 Hz, H-2); 5.56 (1H, dd, J=5.1, 11.4 Hz, H-12); 6.38 (1H, dd, J=0.8, 1.7 Hz, H-14); 7.40 (1H, m, H-15); 7.42 (1H, m, H-16).

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