Use of cleavable coordinating rings as protective groups in the synthesis of a rotaxane with an axis that incorporates more chelating groups than threaded macrocycles.
A new methodology allowing preparation of a linear "unsaturated" [3]rotaxane consisting of an axis incorporating more coordination sites than threaded rings was developed. It was based on the preliminary synthesis of a "saturated" [5]rotaxane consisting of a four-chelating site axis threaded through four macrocyclic components, two of them being cleavable rings incorporating a lactone function and the two others being "secure" non-cleavable rings. The stoppering reaction was based on click chemistry. Subsequently, cleavage and removal of the two lactone-containing macrocycles from the [5]rotaxane in basic medium afforded the desired "unsaturated" [3]rotaxane in quantitative yield.
Laboratoire de Chimie Organo-Minérale, Institut de Chimie, Université de Strasbourg-CNRS/UMR7177, 4 rue Blaise Pascal 67070 Strasbourg-Cedex (France).
Antoine
A
Joosten
Yann
Y
Trolez
Valérie
V
Heitz
Jean-Pierre
JP
Sauvage
click chemistry; copper; molecular machine; protecting groups; rotaxanes