Reaction #1857561

Reaction equation

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

isobutyryl chloride

isobutyryl chloride

→

title compound

Yield 56.2%

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

Yield 56.2%

Solvents

pyridine

Conditions

Workup

1. 1
   workup.ADDITIONwas added
2. 2
   Temperaturecooled to room temperature
3. 3
   Otherquenched with sat. aq. NH4Cl (5 ml)
4. 4
   Extractionextracted with EtOAc (3×10 ml)
5. 5
   DryingThe combined organic extracts were dried over MgSO4
6. 6
   Filtrationfiltered
7. 7
   Concentrationconcentrated to dryness
8. 8
   OtherThe crude residue was purified by flash chromatography (SiO2; EtOAc/hexanes)

Procedure

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]+).

Source