Transition-metal-templated synthesis

Blanco, M.-J., Transition-Metal-Templated Synthesis of Rotaxanes, 23, 125. 

This chapter will be concerned mainly with the transition-metal-templated synthesis of rotaxanes. General features of these compounds, including stereochemical issues, will be addressed at first. The intent, however, is not to... 

III. TRANSITION-METAL-TEMPLATED SYNTHESIS A. Principle and Examples... 

Figure 2.22. Strategies for the transition metal-templated synthesis of catenanes. The metal (in) predisposes two fragments as open chelates (A) (strategy I) or as a macrocyclic chelate (E) and an open chelate (strategy II) in intermediates (B) and (F), respectively. Cyclization of these intermediate complexes with the chain fragments (C) provides the [2]-catenate complex (D).

Figure 2.24. Schematic representation of the principle of transition-metal-templated synthesis of [2]-rotaxanes from macrocyclic chelate (A), metal cation (black disk) and open chelate (B). The latter bears functions X at its extremities, which will be used for anchoring or constructing the stoppers (represented as diamonds). (/) Threading step (//) stoppering step (in) removal of the metal template.

PART II TRANSITION METAL-TEMPLATED SYNTHESIS OF ROTAXANES... 

---