Clay-catalyzed organic reactions: The dimerization of 3,4- dimethoxypropenylbenzene with K-10 montmorillonite clay

Interest in the use of montmorillonite clay as a catalyst in organic synthesis has recently increased, encouraged in part by the availability of the clay, its low cost, and propensity to intercalate organic molecules. Research in this laboratory has recently focused on the reactivity of 3,4-dimethoxypropenylbenzene (1) with K-10, a montmorillonite clay whose interlayer cations have been exchanged for protons. These efforts have been directed toward several related goals. First, through a detailed analysis of product mixtures and comparison with previously reported results of clay reactions with 1, a number of new products have been observed. Second, this montmorillonite has a complex aluminosilicate structure containing both Lewis and Broensted acid sites, and sites capable of generating radical cations from intercalated organic substrates. Therefore, the mechanisms by which these produts might be formed have been studied in an effort to gain a better understanding of the interactions of these sites with organic substrates. In this paper we report our initial observations in this area.