Tug‐of‐War in a Dynamic Helical Peptide: Solvent‐Induced Helix‐Helix Transition of a Lactam‐Bridged Peptide Composed of Point‐ and Axial Chiralities Remote from Each Other

Abstract

The dynamic axial chirality of oligopeptide-bound 2,2'-bipyridine (bpy) residues can be remote-controlled and diastereoselectively locked. A right-handed (P)-3 -helix is first induced in the dynamic helical oligopeptide by an l-valine (l-Val) far from the bpy moiety and the induced axial bpy chirality is diastereoselectively dioxidized. The resulting l-Val-containing linear oligopeptides at the 3,3'-positions retain their (P)-3 -helices independent of the axial chirality (aR or aS) of the N-terminal N,N'-dioxide-bpy unit, while a lactam-bridged dynamic helical oligopeptide exhibits a unique solvent-induced helix-helix transition as a result of competitive helix-inducing biases between the l-Val and (aR) or (aS)-N,N'-dioxide-bpy residues remote from each other along the entire oligopeptide chain in a tug-of-war like manner.

α‐Amino‐iso‐Butyric Acid Foldamers Terminated with Rhodium(I) N‐Heterocyclic Carbene Catalysts

“…The axial chirality could be fixed by oxidation of the pyridyl nitrogens, which gave (a R ) enriched isomers with a d.e . of 26 % [46] . Although the 16 % d.e .…”

“…of 26 %. [46] Although the 16 % d.e . observed in 17 , which has the powerful chiral inducer Cbz(L‐αMeVal) 2 , is comparable to that of the complex described by Yashima and co‐workers, it is poor when compared to the +72 % h.e .…”

“…Instead of point chirality, as in αMeVal, other types of chirality can be incorporated. A biaryl axis with restricted rotation is one such example, where the observation of either diastereoisomers or apparent enantiomers depends upon the rate of rotation around this axis [45,46] …”

“…A biaryl axis with restricted rotation is one such example, where the observation of either diastereoisomers or apparent enantiomers depends upon the rate of rotation around this axis. [ 45 , 46 ]…”

Ultrasensitive Solvatochirochromism of Single Benzene Chromophores

“…[25][26][27][28] Selective solvation of polar or nonpolar domains influences the screw sense into either left-or right-handedness depending on the solvent polarity. [29][30][31][32][33] The chirality control by solvents with inherent chirality is another well-explored solvent-solute interplay, which transfers chirality to self-assemblies or reactions to produce optically active products at multi-hierarchical levels. [34,35] Moreover, deep eutectic solvents with high polarity and ionic conductivity could influence the aggregation with altered supramolecular chirality.…”