反応 #172731

反応方程式

4-methoxycarbonylphenylboronic acid

(1R,3aS,5aR,5bR,7aR,11aR,11bR,13bR)-benzyl 5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-9-(trifluoromethylsulfonyloxy)-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

2-propanol

sodium carbonate monohydrate

→

title compound

収率 68.4%

(1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-benzyl 9-(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

収率 68.4%

溶媒

dioxane

water

反応条件

後処理

1. 1
   その他The flask was attached to a reflux condenser
2. 2
   その他flushed with N2
3. 3
   温度heated
4. 4
   温度to reflux overnight
5. 5
   workup.ADDITIONdiluted with water (75 mL)
6. 6
   抽出The mixture was extracted with ethyl acetate (3×75 mL)
7. 7
   洗浄washed with brine (75 mL)
8. 8
   乾燥The combined organic layers were dried with MgSO4
9. 9
   ろ過filtered
10. 10
    濃縮concentrated under reduced pressure
11. 11
    その他purified by silica gel flash chromatography
12. 12
    workup.ADDITIONThe fractions containing the expected product
13. 13
    濃縮concentrated under reduced pressure

実験手順

To a solution of (1R,3aS,5aR,5bR,7aR,11aR,11bR,13bR)-benzyl 5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-9-(trifluoromethylsulfonyloxy)-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 (6.21 g, 9.18 mmol) in dioxane (25 mL) was added 2-propanol (25 mL) and water (15 mL) followed by sodium carbonate monohydrate (3.42 g, 27.5 mmol), 4-methoxycarbonylphenylboronic acid (2.478 g, 13.77 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.318 g, 0.275 mmol). The flask was attached to a reflux condenser, flushed with N2 and heated to reflux overnight. The mixture was then cooled to rt and diluted with water (75 mL). The mixture was extracted with ethyl acetate (3×75 mL) and washed with brine (75 mL). The combined organic layers were dried with MgSO4, filtered, and concentrated under reduced pressure. The residue was adsorbed to silica gel and purified by silica gel flash chromatography using a 0-20% ethyl acetate in hexanes gradient. The fractions containing the expected product were combined and concentrated under reduced pressure to give the title compound (4.16 g, 6.28 mmol, 68.4% yield) as a white foam. 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 7.92 (d, J=8.24 Hz, 2H), 7.40-7.29 (m, 5H), 7.19 (d, J=8.24 Hz, 2H), 5.28 (dd, J=6.10, 1.83 Hz, 1H), 5.19-5.07 (m, 2H), 4.73 (d, J=1.83 Hz, 1H), 4.60 (s, 1H), 3.90 (s, 3H), 3.04 (td, J=10.91, 4.73 Hz, 1H), 2.20-2.32 (m, 2H), 2.09 (dd, J=17.24, 6.26 Hz, 1H), 1.95-1.82 (m, 2H), 1.69 (s, 3H), 0.97 (s, 3H), 0.95 (s, 3H), 0.92 (s, 3H), 0.91 (s, 3H), 1.75-0.87 (m, 17H), 0.82 (s, 3H).

出典