Chromium(II) chloride-promoted reductive β-elimination of 1,1-dihalo alditols. Synthesis of highly functionalized alk-1-enyl halides

A new general synthetic route to obtain highly functionalized (Z)- and (E)-alk-1-enyl halides is described, where the halogen can be indistinctly F, Cl, Br, and I. The procedure involves CrCl2-promoted reductive elimination of β-O-substituted gem-dihalo alditols easily accessible from carbohydrates. The simplicity and mildness of the reaction conditions and their compatibility with different functional groups increase the synthetic potential of this methodology.