Dehydrobromination of 1,1-diaryl-1,2-dibromoalkanes catalyzed by iron and iron bromides. An ion-pair-mediated reaction?

Abstract

Abstract:The participation of ion-paired Lewis acid1Lewis base in the dehydrohalogenations of 1,2-dibromo-1,l-diarylalkanes catalyzed by F~O and by Fe(I1) and Fe(II1) bromides was investigated. The reactivities of the catalyst employed were correlated with their chemical hardness. The influence of para substituents on the phenyl rings of the substrates and the results obtained in Lewis-acid-catalyzed and thermal dehydrobromination of the same compounds were compared. The experimental results could not be explained in terms of a Lewis-acidcatalyzed dehydrobromination.