Poly ring-closing metathesis

Alternatively, ring closure metathesis reaction is applied to the formation of cyclic polymers, although the main chain does not consist of hydrocarbon. Such a method was reported in the preparation of cyclic poly(THF) as shown in Fig. 33 [112]. Such ring-close metathesis was also applied for a preparation of catenane [113]. 

Ring-closing metathesis Ru/poly(ethylene glycol) [20]... 

Yao described stable and soluble poly(ethylene glycol)-bormd Ru catalysts (10) for the ring-closing metathesis (RCM) of a variety of dienes. Bidentate nonphosphine ligands are in fact promising candidates for the recycling of Ru-carbene complexes, since the formation of chelates is entropicaUy favored at the end of the reaction [Eq. (8)] [20]. 

The macromolecular ruthenium carbene complex 30 with modified poly(ethylene oxide) demonstrated high activity in ring-closing metathesis of some substrates, which transformed into cyclic compounds, with quantitative yield. 

Scheme 20 Synthesis of cyclic poly(MA) by the combination of ATRP and the ring-closing metathesis (RCM) reaction...

A closely related special case of metathesis is the conversion of cycloalkenes under metathesis conditions, known as ring-opening polymerization or metathesis polymerization (see Section 12.2). Macrocyclic polyenes and polymers, called poly-alkenamers, are formed with high stereoselectivity ... 

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