The intermediate geometry of carbonyl/Lewis acid complexes in reactions encompassing nucleophilic addition to saturated ketones, the conjugate nucleophilic addition to enones, and 2 + 4 cycloadditions will be investigated. By use of carefully designed adamantone, decalone, and sterically-directed decalone systems, the controlled pi-binding of a variety of Lewis acids to the carbonyl center will be studied by measuring the extent of binding and the resultant effect on chemical reactivity. The reaction rates of 1,2- and 1,4- nucleophilic additions and 2 + 4 cycloadditions will be measured for systems in which Lewis acid binding to the ketone moiety is in-plane with the ketone as well as via a pi-complex type geometry. Differences between transition and main group metal based Lewis acid will be evaluated, and the effect of saturated versus unsaturated carbonyls on the thermodynamic preference for Lewis acid complexation geometry will be defined. %%% One of the most important aspects of modern chemical research is to define on a molecular level the factors which accelerate reactions and provide for clean, efficient generation of specific targeted products. This grant from the Organic Dynamics Program supports the continuing investigation of the acid catalysis of three important classes of chemical reactions by Professor R. C. Corcoran at the University of Wyoming. The investigation is targeted toward synthesis of chemical species with geometrical constraints that provide specific binding of metallic acid catalysts. Such processes are critical in designing new catalysts with increased efficiency, and will be of significant benefit in controlling synthetic processes of technical importance.
