Reaktion #172873

Reaktionsgleichung

(1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-benzyl 9-(3-fluoro-4-(methoxycarbonyl)phenyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysene-3a-carboxylate

t-butyldimethylsilane

TBAF

→

title compound

Ausbeute 95.0%

(1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-9-(3-fluoro-4-(methoxycarbonyl)phenyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysene-3a-carboxylic acid

Ausbeute 95.0%

Lösungsmittel

HCl

DCE

dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe mixture was flushed with N2
2. 2
   TemperaturThe mixture was cooled to rt
3. 3
   Filtrationwas filtered through a plug of celite and silica gel (washed with 25% EtOAc in hexanes)
4. 4
   EinengenThe filtrate was concentrated under reduced pressure
5. 5
   workup.ADDITIONwas added
6. 6
   SonstigeThe solids that formed
7. 7
   Filtrationwere collected by filtration
8. 8
   Waschenwere washed with water

Vorschrift

To a solution of (1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-benzyl 9-(3-fluoro-4-(methoxycarbonyl)phenyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysene-3a-carboxylate (3.59 g, 5.27 mmol) in DCE (25 mL) was added TEA (1.176 mL, 8.44 mmol), t-butyldimethylsilane (1.749 mL, 10.54 mmol), and palladium(II) acetate (0.118 g, 0.527 mmol). The mixture was flushed with N2 and heated to 60° C. for 1 h. The mixture was cooled to rt and was filtered through a plug of celite and silica gel (washed with 25% EtOAc in hexanes). The filtrate was concentrated under reduced pressure. The residue was diluted with 25 mL of dioxane and TBAF (75% in water) (2.76 g, 7.91 mmol) was added. The mixture was stirred for 30 minutes at rt then was diluted with 50 mL of 1N HCl. The solids that formed were collected by filtration and were washed with water to give the title compound (2.95 g, 4.99 mmol, 95% yield) as a white solid. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.83 (1H, t, J=7.9 Hz), 6.90-7.00 (2H, m), 5.34 (1H, dd, J=6.1, 1.6 Hz), 4.77 (1H, d, J=2.0 Hz), 4.64 (1H, s), 3.94 (3H, s), 3.04 (1H, td, J=10.7, 4.8 Hz), 2.24-2.34 (2H, m), 2.13 (1H, dd, J=17.3, 6.3 Hz), 1.96-2.06 (2H, m), 1.72 (3H, s), 1.03 (3H, s), 1.02 (3H, s), 0.98 (3H, s), 0.93-0.96 (6H, m), 0.91-1.80 (17H, m).

Quelle