Special chemical reactions of dendritic molecules

Since the covalent reactions on the periphery of dendrimers (functionalisation and transfunctionalisation) which immediately spring to mind have already been described in Chapter 3, a number of further, more specialised kinds of reactions will be considered here. These also include reactions in which bonds are formed or broken between core and periphery in the interior of the dendrimer molecules. So far, however, there are more supramolecular (non-covalent reversible) examples in this field (see Section 6.2) than covalent ones, which although somewhat specialised are also highly original and will now be considered in the following Section 6.1.1. 

Frechet and Liang synthesised a fifth-generation benzyl ether dendrimer with 22 internal allyl groups. Subsequent olefin metathesis [1] led on the one hand to intramolecular linking, and on the other hand to creation of a covalent linkage site for olefin-functionalised guests (Fig. 6.1) [2]. In this way, intermolecular cross-linking - between G5 dendrimer molecules - could also be attained. 

Dendrimer Chemistry. Fritz Vogtle, Gabriele Richardt and Nicole Werner Copyright 2009 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-32066-0 

Up to third-generation ruthenium-carbene complexed dendrimers (Fig. 6.2) prepared by Astruc et al. contain a chelating diphosphane, which is sufficiently stable for construction of the dendritic architecture while also sufficiently reactive to permit synthesis of the dendrimer depicted in Fig. 6.3 by ring-opening metathesis polymerisation (ROMP) [3]. 

Branched metallodendrimer catalysts have also been described by van Koten, Hoveyda, and Verdonck [5]. 

---

Bibliography and Notes for Chapter 6 (Special) chemical reactions of dendritic molecules I 247... 

---