Reaction #80767

Reaction equation

potassium tert-butoxide

THF

N-ethoxalyl-2-formyltetrahydroquinoline

THF

water

hydrochloric acid

→

N-ethoxalyl-2-ethoxycarbonylethenyltetrahydroquinoline

Yield 54.0%

Conditions

Workup

1. 1
   workup.ADDITIONAfter the complete addition
2. 2
   workup.STIRRINGthe mixture was stirred for 15 min at room temperature
3. 3
   ExtractionThe mixture was extracted with ethyl acetate
4. 4
   WashThe organic layer was washed three times with brine
5. 5
   Dryingdried over magnesium sulfate
6. 6
   Concentrationconcentrated
7. 7
   OtherThe residue was purified by silica gel column chromatography with 4:1 to 3:1 hexane/ethyl acetate

Procedure

To a solution of diethylphosphonoacetic acid diethyl ester (10.6 g, 47.1 mmol) in THF (100 mL) was added potassium tert-butoxide (5.04 g, 44.9 mmol) at 0° C. The mixture was stirred for 20 min at room temperature. To the solution was added dropwise N-ethoxalyl-2-formyltetrahydroquinoline (11.18 g, 42.8 mmol)in THF (120 mL) at 0° C. After the complete addition, the mixture was stirred for 15 min at room temperature and water and a small amount of diluted hydrochloric acid were added. The mixture was extracted with ethyl acetate. The organic layer was washed three times with brine, dried over magnesium sulfate, and concentrated. The residue was purified by silica gel column chromatography with 4:1 to 3:1 hexane/ethyl acetate to give 7.63 g of N-ethoxalyl-2-ethoxycarbonylethenyltetrahydroquinoline (54%): 1H NMR (270 MHz, CDCl3) δ7.15 (m, 4H), 6.79 (dd, 1H, J=16, 5 Hz), 5.89 (dd, 1H, J=16, 2 Hz), 5.31 (m, 1H), 4.12 (q, 2H, J=7 Hz), 2.73 (t, 2H, J=6 Hz), 2.47 (m, 1H), 1.69 (m, 1H), 1.25 (t, 3H, J=7 Hz), 1.11 (t, 3H, J=7 Hz).

Source