CATALYSIS WITH INORGANIC CATIONS .7. THE CATALYTIC PROCESS OF THE DIELS-ALDER REACTION WITH MAGNESIUM PERCHLORATE IN CH2CL2 - KINETIC INVESTIGATION AND SPECTROSCOPIC DETECTION OF THE COMPLEXED INTERMEDIATE

The 2-arylidene-malonic acid dimethyl ester is a dienophile suitable t o be coordinated by Mg(II). The formation of the dienophile/cation com plex in a ratio 2:1 in a non-coordinating solvent has been demonstrate d by NMR spectroscopy. Kinetic determinations performed in dichloromet hane evidenced the high reactivity of the system. The high affinity fo r Mg(II) of the reacting dienophile allows the reaction to be performe d under catalytic conditions, whose single steps have been clarified b y both spectroscopic and kinetic methods. (C) 1997 Elsevier Science Lt d.