Benzophenone → 9-(Diphenylmethylidene)-9H-fluorene

Participants

Reaction Steps

Dry tetrahydrofuran (500 ml) was added to a mixture of fluorene (10.00 g, 60.16 mmoles) and potassium tert-butoxide (7.43 g, 66.18 mmoles) under nitrogen and stirred at room temperature for 5 minutes. Benzophenone (10.96 g, 60.16 mmoles) was then added as a solid and the reaction mixture was stirred for a further 20 hours under nitrogen at room temperature. Aqueous ammonium chloride (sat., 200 ml) was then added and stirred until the colour had faded. Diethyl ether (100 ml) was added and the aqueous layer separated and extracted with diethyl ether (2×100 ml). The combined organic layers were washed with water (3×200 ml), dried over anhydrous magnesium sulfate and evaporated. The crude product (16.0 g) was recrystallised twice from dichloromethane:hexane (100:200 ml) and then from dichloromethane:acetonitrile (100:200 ml) and then dried under vacuum to give white crystals of 9-(diphenylmethylene)-9H-fluorene (7.34 g).

Provenance & Evidence