Reaktion #8852

Reaktionsgleichung

ammonium chloride

propionaldehyde

tert-butyl 4-acetyl-4-methoxypiperidine-1-carboxylate

tert-Butyl 4-acetyl-4-methoxypiperidine-1-carboxylate

lithium diisopropylamine

→

title compound

Ausbeute 55.9%

tert-Butyl 4-(3-hydroxy-1-oxopent-1-yl)-4-methoxypiperidine-1-carboxylate

Ausbeute 55.9%

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted three times with diethyl ether
2. 2
   Waschenwashed with saturated sodium chloride solution
3. 3
   Trocknendried over sodium sulfite
4. 4
   Filtrationfiltered
5. 5
   Einengenconcentrated
6. 6
   SonstigeThe residue was purified by flash chromatography
7. 7
   Wascheneluting with 40% ethyl acetate/hexanes

Vorschrift

To a solution of tert-butyl 4-acetyl-4-methoxypiperidine-1-carboxylate (0.589 g, 2.29 mmol) from Step A in tetrahydrofuran (20 mL) at −78° C. was added lithium diisopropylamine (0.650 mL, 0.974 mmol) followed by propionaldehyde (0.266 g, 0.330 mL, 4.58 mmol). After 5 min, the reaction mixture was poured into saturated ammonium chloride, and extracted three times with diethyl ether. The organic layers were combined, washed with saturated sodium chloride solution, dried over sodium sulfite, filtered, and concentrated. The residue was purified by flash chromatography eluting with 40% ethyl acetate/hexanes to afford the title compound (0.404 g). MS/EI (acetonitrile/water): m/z 216.1 (M+1−BOC) retention time=2.69 min.

Quelle