Sol-gel routes to supported Friedel-Crafts alkylation catalysts

Aluminosilicate catalysts containing supported ZnCl2 and metal fluoride salts have been prepared using a sol-gel based route, tested and characterized. The activities of these ZnCl2 + metal fluoride catalysts, while greater than "Clayzic" (ZnCI2 supported on montmorillonite KIO) are not as good as supported ZnCl2 only supported on aluminosilicate. Alumina supports have also been prepared via a sol-gel route using various chemical additives to generate a mesoporous structure, loaded with ZnCl2 and tested for activity. The activities for these alumina-supported catalysts are also significantly higher than that of "Clayzic", an effective Friedel-Crafts catalyst. Characterizations of these two types of catalysts were done by magic angle spinning (MAS) NMR, diffuse reflectance infrared (DRIFT) spectroscopy and additionally for the alumina nitrogen adsorption studies were done. Supported aluminum trichloride was also investigated as an alternative to the traditional use of aluminum trichloride.

Synthesis of a 7-Membered Biaryl Guanidine Catalyst and its Use in the Vinylogous Aldol Reaction

The present thesis outlines the preparation of a 7-membered guanidine. Initial efforts to obtain this guanidine via 2-chloro-1,3-dimethylimidazolinium chloride induced ring forming chemistry failed to provide the target in a reproducible fashion. Changing strategies, we were able to obtain the desired guanidine through CuCl mediated amination of a 7-membered thiourea intermediate to arrive at the target. In addition, the catalytic activity of this compound was evaluated in a vinylogous aldol reaction of dibromofuranone and four aromatic aldehydes to generate chiral γ-butenolides with modest to good enantiomeric excess. It was found that electron-poor aldehydes resulted in higher, 81% ee, whereas electron rich aldehydes led to low, 41% ee, levels of enantiomeric excess.