Transition Metal-Catalyzed Novel Cycloadditions for Organic Synthesis

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With this award, the Chemical Synthesis Program in the Division of Chemistry is funding Professor Weiping Tang of the University of Wisconsin-Madison to develop novel transition metal-catalyzed cycloaddition reactions focused on generating valuable seven-membered rings. These new reactions have the potential to fill a significant knowledge gap in organic chemistry and lead to a fundamentally new body of research. Professor Tang is integrating his research into education plans through activities that increase the participation of underrepresented undergraduate and high school students. The broader impact of this work includes improved fundamental understanding on metal catalysis and cycloadditions, new chemical methods for the preparation of medicine and materials, and the training of students for careers in science. The project focuses on the development of rhodium-catalyzed [5+2]-cycloadditions of 3-acyloxy-1,4-enynes with alkynes, alkenes, allenes, and other pi-systems. Highly functionalized seven-membered rings are prepared from these readily available enynes. For example, various tropone-containing compounds can be efficiently synthesized using an alkyne as the 2-carbon component. With an alkene or allene as the 2-carbon component, multiple stereogenic centers are set within the seven-membered rings. Professor Tang is also investigating the mechanism and reactive intermediates involved in these novel [5+2]-cycloadditions. These new cycloaddition methods provide solutions for the longstanding challenge to develop efficient and stereoselective synthetic entries into mono- or polycyclic seven-membered rings.