Pericyclizations of Conjugated Allenes and Other Polyenes

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+he Synthetic Organic Chemistry Program is supporting the work of Dr. William H. Okamura of the Department of Chemistry at the University of California at Riverside. Dr. Okamura is developing thermal reactions that can be carried out at relatively low temperatures that result in the rapid and efficient formation of complex ring systems. These will provide new routes to the complex materials needed in modern agriculture and industry. The purpose of the research is to carry out exploratory mechanistic and synthetic investigations on the manner in which chiral conjugated allenes and other polyenes participate in carbon-carbon and carbon-hetero atom bond forming pericyclization reactions. The significance of this study is that by systematically evaluating pericyclic and other reactions of polyenes that lead to new bond formation, both mechanistic and theoretical insight into these processes should obtain. Moreover, a detailed understanding of how substituents and substitution patterns affect the stereomechanistic course of pericyclizations should lend information to the synthetic chemist as to how to better develop and design synthetic methods. The synthetic impact of the current proposal is that methodology pertinent to the synthesis of chiral polycyclic building blocks should emerge. The topics include the development of an understanding of pi-facial stereoselectivity effects by substituents on electrocyclic processes and exploration of the scope and limitations of the allene variant of electrocyclizations, ı3,3!-sigmatropic shifts and cycloaddition processes.