Foldamer-mediated remote stereocontrol: >1,60 asymmetric induction

An N-terminal L-α-methylvaline dimer induces complete conformational control over the screw sense of an otherwise achiral helical peptide foldamer formed from the achiral quaternary amino acids Aib and Ac6c. The persistent right-handed screw-sense preference of the helix enables remote reactive sites to fall under the influence of the terminal chiral residues, and permits diastereoselective reactions such as alkene hydrogenation or iminium ion addition to take place with 1,16-, 1,31-, 1,46- and even 1,61-asymmetric induction. Stereochemical information may be communicated in this way over distances of up to 4 nm. Reaction at a distance: By inducing a quantitative, persistent preference for right-handed helicity, chirality at one end of an otherwise achiral helical molecule is able to control the stereoselectivity of reactions at sites located up to 60 bonds away, shattering previous records for remote stereochemical control. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.