Macrocycle Synthesis by Chloride-Templated Amide Bond Formation

A new family of pseudopeptidic macrocyclic compounds has been prepared involving an anion-templated amide bond formation reaction at the macrocyclization step. Chloride anion was found to be the most efficient template in the macrocyclization process, producing improved macrocyclization yields with regard to the nontemplated reaction. The data suggest a kinetic effect of the chloride template, providing an appropriate folded conformation of the openchain precursor and reducing the energy barrier for the formation of the macrocyclic product.This work was supported by the Spanish Ministry of Science and Innovation (CTQ2012-38543-C03) and Generalitat Valenciana (PROMETEO/2012/020). V.M.-C. thanks Generalitat Valenciana for a postdoctoral fellowship (APOSTD/ 2013/041)