Alkylation of Bromocyclopropanes and Bromoarenes by Means of Dibutylcopperlithium and Alkyl Halides

Treatment of bromocyclopropanes with excess dibutylcopperlithium in tetrahydrofuran at −48 °C gives the respective organocopper intermediates which upon quenching with excess alkyl halides afford alkylated cyclo-propanes with retention of the configuration. This process is applied to the synthesis of methyl cascarillate. Bromoarenes are also reduced with dibutylcopperlithium and allylarenes are prepared therefrom.