Cation Radicals in Solution

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This research is being funded by the Synthetic Organic Chemistry Program for the research of Dr. Nathan L. Bauld of the Department of Chemistry at the University of Texas at Austin. The work will develop new mild reactions for forming complex ring structures. These structures are found in many of the substances used in agriculture and medicine. The research continues the development of hole-catalyzed pericyclic reactions, both for synthetic purposes and to gain fundamental understanding of the structures and reaction paths of organic cation radicals. The hole-catalyzed Diels-Alder reaction (DA) has undergone extensive development and has recently been exemplified in the synthesis of the sesquiterpene natural product (-)-B-selinene. Further mechanistic, stereochemical, and kinetic studies of this and other pericyclic reactions are planned in order to answer more decisively fundamental questions relating to reaction concert, role selectivity, and directness vs. indirectness. A new and powerful methodology for indirect addition in a net DA sense to highly hindered dienes has been developed and will be refined, extended, and illustrated in the synthesis of compounds in the drimane series. Previous hole-catalyzed direct Diels-Alder applications (e.g. B-selinene) have emphasized the diene/electron rich alkene format. A new and very promising strategy for effecting Diels-Alder cycloadditions in the diene/diene format, which nevertheless produces highly differentiated alkene functionalities, has been observed and will be developed. The newly developed hole-catalyzed vinylcyclobutane rearrangement can be used to achieve net Diels-Alder addition. The hole-catalyzed vinylcyclobutane reaction will also be developed extensively in both a mechanistic and synthetic sense.