%0 Journal Article %A Yamada, Hidekazu %A Furusho, Yoshio %A Yashima, Eiji %D 2016 %T Diastereoselective Imine-Bond Formation through Complementary Double-Helix Formation %U https://acs.figshare.com/articles/journal_contribution/Diastereoselective_Imine_Bond_Formation_through_Complementary_Double_Helix_Formation/2526775 %R 10.1021/ja301430h.s001 %2 https://ndownloader.figshare.com/files/4169770 %K terminal aldehyde group %K diastereoselectivity %K chirality %K amidine residues %K chiral amidine templates %K helix %K amidine dimer strands %K salt bridges %K achiral carboxylic acid monomers %K formation %K achiral linkers %K NMR %K reaction rate %K racemic amine %X Optically active amidine dimer strands having a variety of chiral and achiral linkers with different stereostructures are synthesized and used as templates for diastereoselective imine-bond formations between two achiral carboxylic acid monomers bearing a terminal aldehyde group and racemic 1,2-cyclohexanediamine, resulting in a preferred-handed double helix stabilized by complementary salt bridges. The diastereoselectivity of the racemic amine is significantly affected by the chirality of the amidine residues along with the rigidity and/or chirality of the linkers in the templates. NMR and kinetic studies reveal that the present imine-bond formation involves a two-step reversible reaction. The second step involves formation of a preferred-handed complementary double helix assisted by the chiral amidine templates and determines the overall reaction rate and diastereoselectivity of the amine. %I ACS Publications