A means to an end: Polyethylene chains obtained by catalyzed chain growth on magnesium and exhibiting molar masses up to 5000 g mol−1 have been end‐functionalized in high yield with iodide, azide, and amine reactive end groups (see scheme). The functionalized polyethylenes can be used to generate a range of reactive polyolefins; for example, the azide‐functionalized chain can undergo “click” reactions to afford macromonomers.
The incorporation of functional groups at the end of polyolefin chains offers an opportunity to prepare polyolefin building blocks. The latter can be used to construct polymer architectures based on polyolefins with many desirable properties. For this purpose, the reactivity of the carbon-metal bond formed during a catalytic olefin polymerization process is particularly appealing. The possibility of taking advantage of this reactivity has indeed been enhanced by the discovery of systems in which fast and reversible chain transfer reactions between the active metal center and a main group metal centre are occurring. The recent developments of this catalyzed chain growth (CCG) concept are briefly reviewed. A specific system using a (C 5 Me 5 ) 2 NdCl 2 Li(OEt 2 ) 2 complex in conjunction with nbutyloctylmagnesium is then employed to synthesize an array of end functional polyethylene chains. The potential of these building blocks to build up new macromolecular architectures is discussed.
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