Hemicryptophane Cages with a C1-Symmetric Cyclotriveratrylene Unit

J Org Chem. 2021 Nov 5;86(21):15055-15062. doi: 10.1021/acs.joc.1c01731. Epub 2021 Oct 1.

Abstract

Two new hemicryptophanes combining a cyclotriveratrylene unit with either an aminotrisamide or a tris(2-aminoethyl)amine (tren) moiety have been synthesized. Although a conventional synthesis approach was used, the molecular cages obtained are devoid of the expected C3 symmetry. NMR analyses and X-ray crystal structure determination showed that these hemicryptophanes exhibited C1 symmetry due to the unusual arrangement of the substituents of the cyclotriveratrylene unit. This unprecedented arrangement is related to a change in the regioselectivity of the Friedel-Crafts reactions that led to the CTV cap. This constitutes an original approach to access enantiopure chiral molecular cages with low symmetry.