Premium
Directional Control and Supramolecular Protection Allowing the Chemo‐ and Regioselective Transformation of a Triamine
Author(s) -
Coquière David,
de la Lande Aurélien,
Parisel Olivier,
Prangé Thierry,
Reinaud Olivia
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200901020
Subject(s) - regioselectivity , supramolecular chemistry , funnel , chemistry , selectivity , ligand (biochemistry) , covalent bond , kinetic control , adduct , stereochemistry , combinatorial chemistry , crystallography , crystal structure , organic chemistry , receptor , biochemistry , catalysis
A Zn II ‐funnel complex based on a calix[6]arene ligand decorated with three tris(imidazolyl) arms at one end of the cone and three NH 2 substituents at the other end, acts as a multipoint recognition host for polyfunctionalized guests. The selectivity is ensured by coordination to Zn II , CH–π interaction within the calix cone, and H‐bonding at both rims of the cavity. As a result of these multiple interactions, the host can wrap and orient an unsymmetrical triamine guest with a high selectivity. Furthermore, a proton‐monitored switch between the regio‐isomeric adducts allows reversible inversion of the directionality of the system. Thanks to this directional control, the regioselective mono‐carbamoylation of the unsymmetrical triamine guest was successfully achieved on a preparative scale. This case study shows that a funnel‐like receptor can be used as a supramolecular protecting tool allowing a transformation which would be impracticable with conventional covalent chemistry.