The synthesis and chemistry of a variety of reactive heterocycles will be studied: Part I. Nucleophilic additions to reactive epoxides will be studied in relation to the carcinogenic activation of polycyclic aromatic hydrocarbons, and in relation to the biogenesis of natural products. Part II. Model systems will be studied to mimic the mechanism of oxidations mediated by the flavin cofactored monooxygenases. Part III. Reactive crown ethers, macrocyclic reagents capable of both complexing and reacting selectively with substrates in nonpolar media, will be used in mechanistic and synthetic studies.