Highly reactive metallic nickel, prepared by the lithium metal reduction of nickel iodide using naphthalene as an electron carrier, was found to induce 1, 4-dehalogenation of a, a'-dihalo- o-xylene derivatives at room temperature. The reaction proceeds in the presence of a variety of electron-deficient olefins, giving Diels-Alder cycloadducts in moderate to good yields presumably via the highly reactive intermediate o-xylylene 2. 1, 3-Dibromoindan and 1, 4- ...
