A new copper(II) chloride-promoted rearrangement of N-allylhydrazones has been developed. Treatment of a number of aromatic N-allylhydrazones with copper(II) chloride provides the formation of both a new carbon-carbon bond and a carbon-chloride bond in the same reaction. Substrate studies revealed that the carbon-carbon bond-forming step proceeds by way of a concerted [3,3] sigmatropic rearrangement and selectively generates trans-substituted alkenes.