4-Bromotoluene → 4'-Methyl-biphenyl-3-carboxylic acid ethyl ester

Beteiligte Stoffe

Reaktionsschritte

Magnesium (1.6 g) and p-bromotoluene (10.26 g) in 60 ml of tetrahydrofuran were stirred and warmed until the reaction commenced. When the exothermic reaction had finished, the mixture was refluxed overnight. In a separate flask, 4 ml of DIBAL (1M in toluene) was added to a suspension of bis(triphenylphosphine)palladium(II) chloride (1.4 g) in 100 ml of tetrahydrofuran, followed by ethyl 3-iodobenzoate (11.04 g). To this mixture, the magnesium reagent prepared above was added dropwise, causing an exothermic reaction. The reaction mixture was stirred overnight at room temperature, and then quenched by addition of dilute hydrochloric acid. The mixture was extracted with ether, and the organic layer washed with water, and then saturated brine. The organic layer was separated, dried over sodium sulfate, the solvent evaporated under reduced pressure, and the residue chromatographed on silica gel, eluting with 5% ethyl acetate in heptane, to yield 5.69 g of ethyl 4'-methylbiphenyl-3-carboxylate, a compound of Formula (17), as a pale yellow oil.

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