Azide Chemistry in Rotaxane and Catenane Synthesis

Stephanie Durot/ Julien Frey/ Jean-Pierre Sauvage and Christian Tod/ 

Organic Azides Syntheses and Applications Edited by Stefan Br and Klaus Ban 2010 John Wiley Sons, Ltd. ISBN 978-0-470-51998-1 

Until recently, azides were relatively rare precursors of interlocked molecules and most of the time they were meant to be linked to alkynes using 1,3-dipolar cycloaddition. In this review, we will restrict ourselves to their use in attachment of stoppers to pseudo-rotaxanes and present a selection of the most representative papers. They can be divided into purely organic molecular entanglements and into interlocked molecules prepared by transition metal templated approaches. 

2 Based on Hydrogen Bonding or on Organic Donor-Acceptor Complexes 

Another wide family of purely organic interlocked systems has been developed by Stoddart s group, based on hydrogen bonding and on donor-acceptor interactions. Suitably sized crown ethers can form pseudorotaxane complexes with appropriate secondary dialkylammonium ions which rely on N —H - 0 and C—H - 0 hydrogen bonds for stabiUzation. Similarly, a r-electron rich component, in interaction with a r-electron deficient moiety (traditionally cyclobis(paraquat-p-phenylene), CBPQ T, 21,  

---

Azide Chemistry in Rotaxane and Catenane Synthesis 415 14.2 Purely Organic Rotaxanes and Catenanes... 

---