Reaktion #1350661

Reaktionsgleichung

trifluoroacetic anhydride

Et3N

HCOOH

PPh3

estrone

→

1,3,5(10)-estratrien-17-one

Ausbeute 65.3%

Lösungsmittel

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   Waschenthe organic phase washed with the same solution until the blue color
2. 2
   ExtraktionNext, the solution was extracted with EtOAc
3. 3
   Waschenthe organic phase washed with water
4. 4
   Trocknendried over MgSO4
5. 5
   SonstigeAfter evaporation of the solvent
6. 6
   workup.DISSOLUTIONthe crude estrone-triflate was dissolved in 50 mL of dry DMF
7. 7
   workup.WAITAfter 3 h at room temperature
8. 8
   Sonstigethe solution was quenched with aqueous HCl (5%)
9. 9
   Extraktionextracted with CH2Cl2
10. 10
    WaschenThe organic phase was washed with water
11. 11
    Trocknendried over MgSO4, and solvents
12. 12
    Sonstigeevaporated to dryness
13. 13
    SonstigeThe crude compound was purified by flash chromatography with hexanes/EtOAc (9:1) as eluent

Vorschrift

At 0° C., 1.0 g (3.7 mmol) of estrone (73) was dissolved in 50 mL of dry pyridine and 1.24 mL (7.4 mmol) of trifluoroacetic anhydride (Tf2O) was added slowly to the solution. After 1 h, the crude solution was poured into a cold aqueous solution of CuSO4 (1M) and the organic phase washed with the same solution until the blue color disappear. Next, the solution was extracted with EtOAc and the organic phase washed with water, and dried over MgSO4. After evaporation of the solvent, the crude estrone-triflate was dissolved in 50 mL of dry DMF. To the resulting mixture, we added 1.54 mL (11 mmol) of Et3N, 0.41 mL (11 mmol) of HCOOH, 0.143 mg (0.55 mmol) of PPh3, and 30.8 mg (0.14 mmol) of Pd(OAc)2. After 3 h at room temperature, the solution was quenched with aqueous HCl (5%) and extracted with CH2Cl2. The organic phase was washed with water, dried over MgSO4, and solvents evaporated to dryness. The crude compound was purified by flash chromatography with hexanes/EtOAc (9:1) as eluent to give 615 mg (65% two steps) of 1,3,5(10)-estratrien-17-one (74). White solid; IR ν (film): 1738 (C═O); 1H NMR (CDCl3) δ 0.94 (s, 3H, 18-CH3), 2.94 (m, 2H, 6-CH2), 7.16 (m, 3H, 1-CH, 2-CH, 3-CH), 7.32 (d, J=5.9 Hz, 1H, 4-CH); 13C NMR (CDCl3) δ 13.76 (C-18), 21.51 (C-15), 25.61 (C-11), 26.42 (C-7), 29.29 (C-6), 31.56 (C-12), 35.77 (C-16), 38.04 (C-8), 44.40 (C-9), 47.88 (C-13), 50.49 (C-14), 125.22 (C-3), 125.73 (C-2 and C-1), 128.98 (C-4), 136.37 (C-5), 139.62 (C-10), 220.63 (C-17).

Quelle