Samarium Dibromide, an Efficient Reagent for the Pinacol Coupling Reactions.
The preparation of SmBr2 from Sm2O3 is described.This samarium (II) compound is a powerful one electron reductant able to very efficiently mediate pinacolic couplings.Cross couplings are effective in some cases, for example a chiral diol can be obtained from benzophenone and camphor.Intramolecular pinacolization of a diketone has been performed.