Olefin metathesis ring-opening

Olefin Metathesis Ring-Opening Metathesis Polymerisation... 

Fig. 4.14. The synthesis of polymers by olefin metathesis ring-opening metathesis polymerization (ROMP).

Dragutan, V. Balaban, A. T. Dimonie, M. Olefin Metathesis Ring Opening Polymerization of Cyclo-Olefins-, Wiley-Interscience Chichester, 1985. 

The olefin cross metathesis (CM) can be described as the intermolecular metathesis of alkylidene fragments between two different olefins [133]. It can be farther divided into three main subtypes cross metathesis, ring opening cross metathesis (ROCM) and enyne cross metathesis (ECM) (Scheme 3.9). 

In general, there are three modes of olefin metathesis ring closing metathesis (RCM),M ring opening metathesis polymerization (ROMP),5-6 and cross metathesis (CM).7-9 Although all three have industrial applications, the main use of olefin metathesis for fine chemicals production lies in the modes of CM and RCM (Scheme 28.1). 

Thanks to the development of the Grubbs benzylidene catalyst (2) and other related ruthenium complexes, olefin metathesis has experienced spectacular advances over the past 10 years. The various incarnations of the reaction (acyclic diene metathesis, ring-closing metathesis, ring-opening metathesis polymerization, etc.) have now acquired first rank importance in synthesis. Clearly, the emergence of a similar, generic, efficient catalytic system for con-... 

More complex small molecules can also be made by metathesis cascades and tandem reaction sequences involving olehn metathesis components [41], The examples illustrated in Fig. 4.13 include inter- and intramolecular enyne metathesis between an olefin and an alkyne [42], ring-opening cross metathesis to form new substituted acyclic olefins [43], ring-opening ring-closing sequences... 

Grubbs, R., Risse, W. and Novae, B. The Development of Well-defined Catalysts for Ring-Opening Olefin Metathesis. Vol. 102, pp. 47-72. 

Scheme 2 Different modes of the olefin metathesis reaction cross metathesis (CM), ringclosing metathesis (RCM), ring-opening metathesis (ROM), acyclic diene metathesis polymerization (ADMET), and ring-opening metathesis polymerization (ROMP)...

Several transition metal complexes can catalyze the exchange of partners of two double bonds. Known as the olefin metathesis reaction, this process can be used to close or open rings, as well to interchange double-bond components. 

In the case of other Group 6 metals, the polymerization of olefins has attracted little attention. Some molybdenum(VI) and tungsten(VI) complexes containing bulky imido- and alkoxo-ligands have been mainly used for metathesis reactions and the ring-opening metathesis polymerization (ROMP) of norbornene or related olefins [266-268]. Tris(butadiene) complexes of molybdenum ) and tungsten(O) are air-stable and sublimable above 100°C [269,270]. At elevated temperature, they showed catalytic activity for the polymerization of ethylene [271]. 

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