Reaction #741629

Reaction equation

HCl

Dry Ice

indene

butane

→

indene-3-carboxylic acid

Yield 80.0%

Solvents

H2O

ethyl ether

Conditions

Workup

1. 1
   Extractionextracted with ethyl ether
2. 2
   OtherRecrystallization from benzene

Procedure

To a stirred solution of indene (21.9 mL, 188 mmol) in 150 mL of dry ethyl ether was added 129 mL (200 mmol) of η-BuLi dropwise at room temperature over 30 minutes with the evolution of butane. The rust colored mixture was refluxed for 2 h, and then poured in a thin stream onto 40 g of Dry Ice. The mixture was shaken at room temperature for 2 h, after which time 1 L of H2O was cautiously added. The aqueous layer was acidified with 10% HCl and then extracted with ethyl ether. Recrystallization from benzene gave 20 g (80%) of indene-3-carboxylic acid as yellowish crystals.

Source