1,4-Dibromobenzene → Benzene, 1-bromo-4-(2-propenyl)-

Participants

Reaction Steps

At 5° C., a solution of allylbromide (5.64 g, 46.6 mmol) in THF (40 mL) is slowly added to the Grignard reagent freshly prepared from 1,4-dibromobenzene (10.0 g, 42.4 mmol) and Mg-turnings (1.13 g, 46.6 mmol) in THF. The reaction mixture becomes slightly warm and a fine precipitate forms. Upon completion of the addition, the suspension is stirred at rt for 1 h before it is diluted with diethyl ether and washed with two portions of 1 N aq. HCl and one portion of water. The wash solutions are extracted twice with diethyl ether. The organic extracts are combined, dried over MgSO4 and evaporated. The crude product is purified by CC on silica gel eluting with heptane:EA 9:1 to give 1-allyl-4-bromo-benzene (5.50 g) as a colourless oil.

Provenance & Evidence