Lithium chromium(I) dihydride: A novel reagent for the versatile reductivemetathesis, reductive cyclization, oligomerization, or polymerization of diverse organic substrates

The novel reductant of empirical formula LiCrH2 has been efficiently genera ted from CrCl3 and 4 equiv of n-butyllithium in THF and can, be isolated an d characterized as a dark red-brown LiCl-free complex, LiCrH2 . THF, by a c ombination of elemental, gasometric, chemical, IR, and ESR analyses. Withou t separation from the LiCl byproduct, this reductant is reactive toward a w ide range of sigma- and pi-heteroatomic bonds, effecting reductive cleavage or coupling, oligomerization, and even polymerization of diverse organic s ubstrates.