Electrophilicity of Cu-bound Nitriles: Toward a Method for [2+2+2] Cyclizations

Abstract

Copper nitrile systems were explored to determine the change in nitrile nucleophilicity upon coordination to copper. Both Cu(I) and Cu(II) were explored. Complexes bearing electronwithdrawing nitriles and electron-donating nitriles were analyzed using FTIR spectroscopy. The findings that Cu(I) is more reactive than Cu(II) and that an electron-withdrawing functional group on the nitrile allows better coordination are being applied to determine conditions suitable for nitrile cyclotrimerization to generate triazines. Such a synthesis could provide a cheap and sustainable alternative transition metal for promoting cyclotrimerization reactions than is currently available. Another pathway to form a copper-bound intermediate to ultimately produce triazines is under investigation. A (Z)-4-(phenylamino)pent-3-en-2-one was formed from acetylacetone and aniline. This was subsequently reacted with copper to produce a copper-bound product.