Exploration of Nitrogen-Tethered [5+2] Oxidopyrylium-Alkene Based Cycloadditions
T. Andrew Mitchell
[5+2] cycloadditions proceeding through oxidopyrylium-alkene intermediates are efficient means by which various bridged polycyclic ethers may be accessed. Since polycyclic ethers are common biological structures and scaffolds, further investigation into this reaction is warranted to expand available chemical space. While intermolecular [5+2] cycloadditions are generally less favorable, the inclusion of an alkene tether allows for the study of the more favorable intramolecular [5+2] cycloaddition. With the goal of developing chemo-, regio-, stereoselective [5+2] oxidopyrylium-alkene cycloadditions, various alkene-tethers were appended to Maltol-derived substrates to explore the scope and limitation of this reaction. Current work is focused on Maltol-derived substrates that include nitrogen-containing alkene tethers. These substrates were accessed by alkylation, reductive amination, and Grubbs-Hoveyda cross metathesis to produce unique Maltol-derived alkenes for impending cyclization. The resulting [5+2] cycloadditions have provided insight into the reaction pathway of this powerful reaction.
Grabowski, Jake, "Exploration of Nitrogen-Tethered [5+2] Oxidopyrylium-Alkene Based Cycloadditions" (2018). University Research Symposium. 67.