ELECTROCHEMICAL STUDIES OF NI(CYCLAM)(2-CATALYZED ANNULATION REACTIONS())

Cyclic voltammetry and preparative-scale electrochemical studies on th e intramolecular cyclization of allyl 2-halophenyl ethers catalyzed by Ni(II)-cyclam complexes leads us to propose a mechanism involving Ni( I) and Ni(III) intermediate species. The role of Mg2+ ions in the reac tivity and selectivity of the process is discussed. The Nit cyclam)Br- 2-catalyzed electrosynthesis of dihydrobenzofurans and dihydrobenzopyr ans from unsaturated side-chain aryl halide derivatives is effected in good yields in the presence of a magnesium anode.