Reaction #696726

Reaction equation

benzyl alcohol

3-cyclopentene-1-carboxylic acid

diphenylphosphoryl azide

triethylamine

→

benzyl N-(3-cyclopenten-1-yl)carbamate

Solvents

benzene

benzene

Conditions

Workup

1. 1
   workup.ADDITIONwas added over 20 minutes
2. 2
   TemperatureThe solution was refluxed for 2 hours
3. 3
   TemperatureThe solution was refluxed for 20 hours
4. 4
   Temperaturecooled
5. 5
   Concentrationconcentrated in vacuo to a brown oil
6. 6
   WashA solution of the oil in ethyl acetate (600 mL) was washed with 0.5 N hydrochloric acid (300 mL)
7. 7
   Dryingwater (2×350 mL), then saturated aqueous sodium bicarbonate (300 mL), and dried (sodium sulfate)
8. 8
   OtherEvaporation
9. 9
   workup.WAITleft title compound as white solid (41.0 g, 69%)
10. 10
    OtherRecrystallization of such a sample from ethyl acetate-hexanes

Procedure

A solution of 3-cyclopentene-1-carboxylic acid (Depres and Greene, J. Org. Chem. 1962, 27:2395-2398) (30.5 g, 0.272 mole) in dry benzene (360 mL) was stirred while a solution of diphenylphosphoryl azide (Aldrich, 74.85 g, 0.272 mole as 97%) and triethylamine (41.7 mL, 0.299 mole) in benzene (130 mL) was added over 20 minutes. The solution was refluxed for 2 hours and then benzyl alcohol (32.4 mL, 0.313 mole) was added. The solution was refluxed for 20 hours, cooled, and concentrated in vacuo to a brown oil. A solution of the oil in ethyl acetate (600 mL) was washed with 0.5 N hydrochloric acid (300 mL), then water (2×350 mL), then saturated aqueous sodium bicarbonate (300 mL), and dried (sodium sulfate). Evaporation left title compound as white solid (41.0 g, 69%), 1H-NMR consistent with structure. Recrystallization of such a sample from ethyl acetate-hexanes gave benzyl N-(3-cyclopenten-1-yl)carbamate as colorless waxy crystals, m.p. 56-57° C.

Source