ISMSC 2007 - Università degli Studi di Pavia

PSB 49
On Sokolov’s approach to a Molecular Knot using Ring Closing Metathesis
Pirmin Rösel, a Christopher Smith, a Catherine E. Housecroft, a Edwin C. Constable a
a Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland
We all meet knots in our daily lives and most of us are fascinated with their unique topology.
More importantly, knots are also found in proteins and DNA and hence play an important role in
nature [1].
An early approach towards a molecular knot is Sokolov’s application of an octahedral
tris(chelate) template [2].
We synthesised the homoleptic iron(II)-complex 1 which has terminal alkene functionalities.
NMR spectroscopic and ESI-MS measurements confirm the successful trifold intramolecular
Ring Closing Metathesis. Our current efforts are concentrated on the separation and
characterisation of 3 and its isomers.
[1] Molecular Catenanes and Knots; Sauvage, J.-P., Dietrich-Buchecker C. Eds.; Wiley: New
York, 1999 and ref. herein.
[2] V. I. Sokolov, Russ. Chem. Rev. 1973, 42, 452.
New route for the C-functionalisation of macrocyclic polyamines
Yoann Rousselin, Franck Denat, Frédéric Boschetti, Roger Guilard
Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB - UMR CNRS 5260)
9, avenue Alain Savary, BP 47870, 21078 DIJON - FRANCE
Cyclic tetraamines have received considerable attention owing to their coordination properties
towards various metal cations. The increasing need of finely tuned macrocycles requires the
development of new synthetic tools for the preparation of such ligands. The research in this field
has been focused on the synthesis of bifunctional chelating agents (BFCs or BCAs) based on a
cyclic amine containing two kinds of functional groups, one for the coordination of the guest,
another one for the anchoring of the macrocycle onto a solid support or an antibody. The
attachment of one functional group on the carbon skeleton is particularly advantageous since
the four secondary amines are available for further functionalisation with chelating arms.
Recently, we have proposed a very convenient route for the synthesis of a wide range of Cfunctionalised
macrocycles using bisaminal intermediates. 1,2 However, this approach still implies
the use of a biselectrophilic reagent containing the desired functional group on a carbon atom.
Here we would like to present a new method of C-functionalisation of linear polyamines
proceeding through the use of chloroacetaldehyde and benzotriazole (Bt) to help in the
cyclization reaction. The displacement of the benzotriazole group by various nucleophiles gives
access to new C-functionalised cyclens and [13]aneN4.
N
N
H
R
Me
R = H, Me
n = 0, 1
N
N
H
chloroacetaldehyde
benzotriazole
N
N
R
n = 0, 1
N
N
Me
Bt
Nucleophilic agent
N
N
R
n = 0, 1
N
N
Me
Nu
acidic condition
[1] F. Boschetti, F. Denat, R. Guilard, H. Ledon, H. Chollet and J.L. Babouhot WO 03/029228.
[2] F. Boschetti, F. Denat, E. Espinosa, J.-M. Lagrange and R. Guilard, Chem. Commun., 2004,
588-589.
NH
NH
n = 0, 1
HN
HN
Nu
PSB 50