New Cycloaddition and Annulation Strategies for Organic Synthesis

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With the support of the Chemical Synthesis Program in the Division of Chemistry, Professor Rick L. Danheiser of the Massachusetts Institute of Technology will study the development of new methods for the chemical synthesis of cyclic organic molecules. Synthesis is often described as the enabling technology of chemistry. The synthetic methods developed in the proposed research will provide researchers in both academia and industry with new tools for the synthesis of important organic compounds with applications in medicine, agriculture, electronics, and other areas. Carbocyclic and heterocyclic ring systems are incorporated in the chemical structures of numerous biologically and medicinally important compounds, and the development of highly efficient methods for their synthesis has great value in providing improved access to molecules with important applications in these areas. The goal of this research program is the development of new strategies with the power to dramatically streamline the synthesis of these classes of compounds. The utility of these new methods will be demonstrated by their application to the synthesis of several naturally occurring compounds that have known activity as antitumor agents, but which are not available in quantity from their sources in nature. The graduate students supported under this grant will serve as coordinators for the MIT Outreach Program, which each year visits ca. 25 high schools in the New England region providing presentations on chemistry and careers in science. Approximately 1200-1500 high school students attend these presentations each year, with many of the students being members of underrepresented groups in STEM (science, technology, engineering and mathematics) fields.The aim of the proposed research is to advance the ability of chemists to develop efficient syntheses of several important classes of organic compounds including polycyclic aromatic molecules, heterocyclic systems such as indoles and carbazoles, and eight-membered carbocyclic compounds. The methods that will be investigated involve mechanistically novel transformations and these studies are expected to advance our understanding of the chemistry of unusual reactive species such as strained carbocyclic rings, vinylketenes, and several other classes of highly unsaturated conjugated molecules. From the perspective of sustainability, the methodology under development has several attractive features. Most of the methods are highly atom economical, i.e., all of the atoms of the reactants are incorporated in the products, minimizing the generation of chemical waste. In addition, most of the new cycloadditions to be developed are triggered simply by heat or light, avoiding the need for even catalytic amounts of reagents (especially heavy metal catalysts). The graduate students supported under this program will receive training to develop their skills as synthetic chemists, and will also receive training in scientific ethics and training to develop their oral and written communication skills.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.