Reaction #86295

Reaction equation

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

triethylsilane

→

desired product

Yield 30.0%

2-oxo-2-((10S,13S,16R,17S)-10,13,16-trimethyl-3-oxo-2,3,6,7,8,10,12,13,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-17-yl)ethyl acetate

Yield 30.0%

Solvents

methylene chloride

Conditions

Workup

1. 1
   OtherThe reaction was evaporated in vacuo
2. 2
   Otherchromatographed on fine silica gel (600 g) in 10-15% ethyl acetate in methylene chloride
3. 3
   OtherOne fraction of 700 mL was collected

Procedure

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).

Source