An unprecedented ring-opening mode of trans-2-aroyl-3-aryl-cyclopropane-1,1-dicarboxylates involving the cleavage of the C2C3 bond of the cyclopropane ring mediated by PCl5 was disclosed. This reaction provides an efficient metal-free way to functionalized stereodefined trisubstituted Z-vinyl chlorides in moderate to good yields. A tentative mechanism for the reaction has been proposed.