Reaktion #1857561

Reaktionsgleichung

tert-butyl ((3S,7S,8R,9S)-8-butyl-7-hydroxy-9-methyl-2-oxooxonan-3-yl)carbamate

isobutyryl chloride

isobutyryl chloride

→

title compound

Ausbeute 56.2%

(2S,3S,4S,8S)-8-((tert-butoxycarbonyl)amino)-3-butyl-2-methyl-9-oxooxonan-4-yl isobutyrate

Ausbeute 56.2%

Lösungsmittel

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   Temperaturcooled to room temperature
3. 3
   Sonstigequenched with sat. aq. NH4Cl (5 ml)
4. 4
   Extraktionextracted with EtOAc (3×10 ml)
5. 5
   TrocknenThe combined organic extracts were dried over MgSO4
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated to dryness
8. 8
   SonstigeThe crude residue was purified by flash chromatography (SiO2; EtOAc/hexanes)

Vorschrift

To a solution of tert-butyl ((3S,7S,8R,9S)-8-butyl-7-hydroxy-9-methyl-2-oxooxonan-3-yl)carbamate (0.405 g, 1.179 mmol) in pyridine (3.4 mL) was added DMAP (0.029 g, 0.236 mmol) followed by the slow addition of isobutyryl chloride (0.247 ml, 2.36 mmol) at room temperature. The reaction was warmed to 50° C. and stirred for 3 h, at which point additional isobutyryl chloride (0.247 ml, 2.36 mmol) was added. The reaction was stirred at 50° C. for an additional 14 h, cooled to room temperature, quenched with sat. aq. NH4Cl (5 ml), and extracted with EtOAc (3×10 ml). The combined organic extracts were dried over MgSO4, filtered, and concentrated to dryness. The crude residue was purified by flash chromatography (SiO2; EtOAc/hexanes) to give the title compound (0.274 g, 0.663 mmol, 56%) as a colorless oil: 1H NMR (400 MHz, CDCl3) δ 5.15 (d, J=8.3 Hz, 1H), 4.91-4.84 (m, 1H), 4.79 (dq, J=10.0, 6.3 Hz, 1H), 4.27-4.16 (m, 1H), 2.60-2.44 (m, 1H), 2.23 (dt, J=13.8, 7.1 Hz, 1H), 2.15-1.99 (m, 3H), 1.73 (tdd, J=13.0, 7.3, 2.3 Hz, 1H), 1.57-1.46 (m, 1H), 1.44 (s, 9H), 1.34 (d, J=6.4 Hz, 4H), 1.33-1.19 (m, 5H), 1.18-1.12 (m, 6H), 1.04-0.94 (m, 1H), 0.87 (t, J=7.0 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 175.41, 172.91, 154.98, 79.76, 74.44, 73.12, 52.42, 45.44, 34.24, 33.73, 33.32, 30.88, 28.29, 27.38, 23.25, 19.19, 19.03, 18.88, 18.79, 18.02, 13.82; ESIMS m/z 436 ([M+Na]+).

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