Reaction #480637

Reaction equation

cyclopentane carboxylic acid methyl ester

5-iodo-2-pentanone ethylene ketal

lithium diisopropylamide tetrahydrofuran

cyclohexane

→

pale yellow oil

Yield 97.5%

1-(4-(Ethylenedioxy)Pentyl)Cyclopentane Carboxylic Acid Methyl Ester

Yield 97.5%

Solvents

THF

brine

THF

Conditions

Workup

1. 1
   Temperaturewhile maintaining temperature of −70° C
2. 2
   workup.WAITAfter srirring for 1 h at −70° C.
3. 3
   Temperatureto warm to room temperature overnight
4. 4
   Otherthe organic layer was separated
5. 5
   ExtractionThe aqueous layer was extracted with ether (20 mL)
6. 6
   Washthe combined organic layers were washed with brine (10 mL)
7. 7
   Dryingdried over anhydrous magnesium sulfate
8. 8
   Otherevaporated to dryness

Procedure

A solution of lithium diisopropylamide-tetrahydrofuran 1.5M solution in cyclohexane (15 mmol, 10 mL) was cooled to −70° C., and a solution of cyclopentane carboxylic acid methyl ester (10 mmol, 1.28 g) in THF (10 mL) was added dropwise over 15 min, maintaining the internal temperature at −60 to −70° C. The yellow solution was stirred 1 h at −70° C. and a solution of 5-iodo-2-pentanone ethylene ketal (10 mmol, 1.28 g) in THF (10 mL) was added over 15 min, while maintaining temperature of −70° C. After srirring for 1 h at −70° C., the reaction mixture was allowed to warm to room temperature overnight. The reaction mixture was poured into brine (150 mL) and the organic layer was separated. The aqueous layer was extracted with ether (20 mL), the combined organic layers were washed with brine (10 mL), dried over anhydrous magnesium sulfate and evaporated to dryness to give 2.5 g (97%) of a pale yellow oil.

Source