Directional control and supramolecular protection allowing the chemo- and regioselective transformation of a triamine.
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-pi 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.
Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR CNRS 8601, Université Paris Descartes, 45 rue des Saints-Pères, 75006 Paris, France.
David
D
Coquière
Aurélien
A
de la Lande
Olivier
O
Parisel
Thierry
T
Prangé
Olivia
O
Reinaud
D047250:Calixarenes / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry; D011073:Polyamines / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry
D011073:Polyamines; D014867:Water; D047250:Calixarenes; D015032:Zinc; D009584:Nitrogen