Physical Sciences and Mathematics Commons^™

Accessing Improbable Foldamer Shapes With Strained Macrocycles., Ko Urushibara, Yann Ferrand, Zhiwei Liu, Kosuke Katagiri, Masatoshi Kawahata, Estelle Morvan, Ryan D'Elia, Vojislava Pophristic, Aya Tanatani, Ivan Huc

Faculty Scholarship for the College of Science & Mathematics

The alkylation of some secondary amide functions with a dimethoxybenzyl (DMB) group in oligomers of 8-amino-2-quinolinecarboxylic acid destabilizes the otherwise favored helical conformations, and allows for cyclization to take place. A cyclic hexamer and a cyclic heptamer were produced in this manner. After DMB removal, X-ray crystallography and NMR show that the macrocycles adopt strained conformations that would be improbable in noncyclic species. The high helix folding propensity of the main chain is partly expressed in these conformations, but it remains frustrated by macrocyclization. Despite being homomeric, the macrocycles possess inequivalent monomer units. Experimental and computational studies highlight specific fluxional …