Iodine → Stilbene

Participants

Reaction Steps

3.3 g. (0.01 mole) cis-stilbene bromide are dissolved in 100 ml. anhydrous 1,2,3,4-tetrahydro-9-fluorenone. This solution is diluted with 1200 ml. anhydrous cyclohexane and mixed with 1.7 g. iodine. The solution is illuminated, while passing in nitrogen, with a laboratory immersion lamp with cooling tube of the type TQ 150 (Hanau) for 12 to 14 days. The reaction is monitored by thin layer chromatography (dichloromethane/petroleum ether (b.p. 30° to 50° C.) 1:2 v/v). The organic phase is shaken out three times with 300 ml. amounts of thiosulphate solution in order to remove excess iodine. After drying over anhydrous magnesium sulphate, the organic phase is evaporated on a rotary evaporator and the crude product obtained is recrystallised from petroleum ether (b.p. 60° to 90° C.). Yield 1.55 g. (47% of theory).

Provenance & Evidence