In this project both mechanistic and synthetic aspects of alkene ozonolysis will be investigated. The mechanistic studies will focus on the determination of the stereochemistry of the elusive carbonyl oxide intermediate, making use of an intramolecular trapping protocol which will permit reliable assignment of syn-anti geometry to carbonyl oxides produced by alkene ozonolysis. The effect of various substituents in determining carbonyl oxide stereochemistry will also be studied, as will the influence of ring size in cycloalkenes. These studies will provide important information for refinement of theoretical models which account for the overall stereoselectivity of alkene ozonolysis. Another mechanistic study will investigate the role of dioxirane-like intermediates in ozonide decomposition through O-labelling experiments. In the synthetic area, the cationic ring expansion of certain ozonides to the 1,2,4-trioxane system will be investigated in terms of the scope of the reaction and its application to the synthesis of the antimalarial artemisinin. %%% With this award the Synthetic Organic Program of the Chemistry Division will support the research of Dr. William H. Bunnelle of the Department of Chemistry at the University of Missouri - Columbia. Both mechanistic and synthetic aspects of reactions of hydrocarbons containing double bonds (alkenes) with ozone will be investigated. Some of the proposed intermediates in the ozonolysis process may be significant with regard to the toxicity of fatty acid ozonides.
