Nitrogen-containing heterocycles play a fundamental role in the make-up of proteins, nucleic acids, and enzymes. As a consequence, the further understanding of biochemistry depends heavily on the functionalization of a nitrogen-containing heterocycle core. Despite the importance of such basic molecules, general methods for synthesizing and functionalizing nitrogen-containing heterocylces remain scarce. Recent advances in transition metal catalyzed carbon-nitrogen bond-forming reactions are currently unable to solve these problems. One successful application involves imino zirconocene complexes that will stoichiometrically insert alkynes to form pyrroles. Similar imido zirconocene complexes have proven to be more reactive than classical imido compounds but their synthetic capabilities have not been developed. The proposed research involves a detailed investigation of the synthetic scope of transition metal imido complexes in organic syntheses and biomimetic polymer chemistry. Insertion of nitriles to regenerate an imido bond is the premise for catalytic synthesis of heterocycles such as pyrrolidines, pyrroles, and piperidine. Because of the unprecedented reaction between nitriles and imido zirconocenes, detailed mechanistic analyses will be done. Synthesis of small molecules will be optimized, and successive nitrile insertions to encompass polymerization will be explored. Resulting polymers will be analyzed for biomimetic qualities.
