Reaction Steps
A mixture of 3.3 g (8.6 mM) of 2-oxo-2-((10S,13S,16R,17S)-10,13,16-trimethyl-3-oxo-6,7,8,10,12,13,14,15,16,17-decahydro-3H-cyclopenta[a]phenanthren-17-yl)ethyl acetate, chlorotris(triphenylphosphine)rhodium(I) (Wilkinson's Catalyst, 480 mg, 0.52 mM), triethylsilane (1.4 mL, 1.0 g, 8.8 mM) and methylene chloride (15 mL) was warmed to 40° C. and stirred until most of the starting material was gone, as determined by thin layer chromatography. The reaction was evaporated in vacuo and chromatographed on fine silica gel (600 g) in 10-15% ethyl acetate in methylene chloride. One fraction of 700 mL was collected, followed by twelve 200 mL fractions. A 1.0 g quantity of desired product (30% yield) was obtained by evaporation of fractions 6-12. (Starting material was obtained from fraction 13, 0.7 g, 20% recovery). NMR (500 MHz, CDCl3, TMS): δ 0.68 (s, 3H), 0.98 (d, 3H, J=6.5 Hz), 1.12 (m, 1H), 1.33 (s, 3H), 1.47 (m, 1H), 1.57 (m, 1H), 1.69 (m, 1H), 1.99 (m, 1H), 2.18 (s, 3H), 2.07-2.29 (m, 6H), 2.36 (d, 1H), 2.50 (m, 3H), 2.79 (m, 1H), 4.48 (d, 1H, J=17 Hz), 4.73 (d, 1H, J=17 Hz), 5.50 (s, 1H), 5.75 (s, 1H).
