Shape persistent macrocyde

In the kinetic approach, the building blocks of the macrocyde are connected to a linear oligomer that subsequently has to undergo an intramolecular bond formation in order to produce the cyclic compound. There are in principle two ways to perform this either the oligomer is formed independently and then cydized in a separate reaction vessel or oligomer formation and cyclization are performed in a one-pot reaction. Both approaches are described for a variety of shape-persistent macrocydes with different backbone structures as outlined in the examples below. 

These results show unambiguously that templates are an attractive alternative to the tedious precursor synthesis commonly used for the preparation of shape-persistent macrocydes. They allow the preparation of symmetrically and even of nonsymmetrically functionalized PAMs in high yields. Moreover, the increased amount of the shape-persistent macrocyde in the crude product simplifies the purification procedure in most cases. However, both the supramolecular and the covalent template approach require the presence of appropriate functional groups that bind (are bound) to the template. 

A different approach towards shape-persistent macrocydes is macrocycle preparation under thermodynamic control, i.e. if the desired structure is the most stable under the given conditions and the cydization reaction is reversible, one might be able to obtain a single macrocyclic product in quantitative yield although the reaction starts with small building blocks [41, 42],... 

High-yield Synthesis of Shape-persistent Phenylene-Ethynylene Macrocydes... 

Highly Effident Formation of Shape-Persistent Oligoamide Macrocydes... 

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