Acid- and Metal-Catalyzed Organic Reactions

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The discovery and development of new chemical reactions are major foci of research activity in organic chemistry. The reactions and classes of reactions which have found the broadest applicability in organic chemistry are those that address the issues of regio-, stereo- and enantiocontrol and are compatible with a variety of functional groups. Reactions which form multiple bonds, rings and/or stereocenters are particularly important tools for the efficient assembly of complex molecular structures. The long-term objective of our research program is to develop novel synthetic methodologies for the construction of different ring systems, including: nitrogen-containing heterocyclic compounds, spirocyclic compounds, attached-ring compounds and polycyclic compounds. These ring systems are present in many biologically important natural products, which have found use in anti-HIV, anticancer, antiviral and antiretroviral researches. Synthetic methods which allow for the rapid construction of these ring systems with high regio-, stereo- and enantioselectivities would be very useful. Acid and metal-catalyzed reactions are of particular interest due to their ability to control the regio-, stereo- and enantioselectivities by fine-tuning of the metal and surrounding ligands. The use of transition metals in organic synthesis has increased dramatically in the last two decades. Transition metal catalysts provide new opportunities for highly selective reactions that are not achievable by traditional synthetic methods. We will investigate: (i) Ru-catalyzed [2+2] cycloadditions between an alkene and an alkyne; (ii) Ru-catalyzed [3+2] and [3+3] cycloadditions of aziridines; (iii) Acid and metal-mediated reactions of cyclopropanated bicyclic alkenes; and (iv) Synthesis of novel chiral helical organic structures/polymers. During the studies described herein towards the long-term goal, several short-term goals will be accomplished. These short-term objectives include: the development of novel acid and metal-catalyzed reactions, studies on various aspects of these acid and metal-catalyzed reactions, including addressing the questions of reactivity, regio-, stereo- and enantioselectivities, investigation of intramolecular and asymmetric versions of these reactions, and the development of novel metal catalysts and ligands. This research program is important not only in science development but also provides the training for students interested in careers in pharmaceutical and chemical industries.