Ring-opening metathesis polymerization applications

When a mixture of alkenes 1 and 2 or an unsymmetrically substituted alkene 3 is treated with an appropriate transition-metal catalyst, a mixture of products (including fi/Z-isomers) from apparent interchange of alkylidene moieties is obtained by a process called alkene metathesis. With the development of new catalysts in recent years, alkene metathesis has become a useful synthetic method. Special synthetic applications are, for example, ring-closing metathesis (RCM) and ring-opening metathesis polymerization (ROM) (see below). 

Kiessling, L. L. Owen, R. M. Synthesis and Applications of Bioactive Polymers Generated by Ring-opening Metathesis Polymerization. 

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). 

Sutthasupa S, Shiotsuki M, Sanda F (2010) Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials. Polym J 42 905-915... 

These complexes are suitable for the ring-opening metathesis polymerization of functionalized norbomenes in water,148 as well as ring-closure reactions via ethylene elimination.149 The versatility of these catalysts has given rise to extensive applications in organic synthesis,150151 including, for example, amino acid derivatives.152... 

Unsaturated polymers can be produced by means of ring-opening metathesis polymerization (ROMP) of cyclic alkenes. These unique polymers can also be produced via intermolecular Acyclic Diene Metathesis (ADMET). Dienes can also react intramolecularly via Ring Closing Metathesis (RCM) to afford cyclic products. RCM is often applied to synthesis of compounds for fine chemical and pharmaceutical application. Generic examples of these reactions are shown in Figure 2. 

Olefin metathesis (OM) has proven to be one of the most important advances in catalysis in recent years based on the application of this chemistry to the synthesis of polymers and biologically relevant molecules [1-10]. This unique transformation promotes chain and condensation polymerizations, namely ring opening metathesis polymerization and acyclic diene metathesis polymerization (ADMET). Applications of metathesis polymerization span many aspects of materials synthesis from cell-adhesion materials [11] to the synthesis of linear polyethylene with precisely spaced branches [12]. 

Dense carbon dioxide represents an excellent alternative reaction medium for a variety of polymerization processes. Numerous studies have confirmed that CO2 is a potential solvent for many chain growth polymerization methods, including free-radical, cationic, and ring-opening metathesis polymerizations. Carbon dioxide has also been demonstrated to be an effective solvent for step-growth polymerization techniques. Advances in the design and synthesis of surfactants for use in CO2 will allow compressed CO2 to be utilized for a wide variety of polymerization systems. These advances may enable carbon dioxide to replace hazardous VOCs and CFCs in many industrial applications, making CO2 an enviromentally responsible solvent of choice for the polymer industry. 

Okoroanyanwu, T. Shimokawa, J.D. Byers, and C.G. WiUson, AUcyclic pol3Tners for 193 nm resist applications synthesis and characterization, Chem. Mater. 10(11), 3319 3327 (1998) U. Okoroanyanwu, J.D. Byers, T. Shimokawa, and C.G. Willson, AUcyclic pol3uners for 193 nm resist appUcations Uthographic evaluation, Chem. Mater. 10(11), 3328 3333 (1998) U. Okoroanyanwu, T. Shimokawa, J.D. Byers, and C.G. Willson, Pd(II) catalyzed addition and ring opening metathesis polymerization of aUcyclic monomers routes to new matrix resins for... 

A large number of applications involve the synthesis of polymers by either ring-opening metathesis polymerization (ROMP), which transforms cyclic olefins into unsaturated polymers (Fig. 4.14) [46,47], or acyclic diene metathesis polymerization (ADMET), which converts acyclic olehns into polymers (Fig. 4.15)... 

With the work by Grubbs et al. [27] and Herrmann et al. [28], the use of ruthenium carbene complexes as homogeneous catalysts for the ROMP (Ring-Opening Metathesis Polymerization) of olefins was estabhshed (see Section 2.4.4.3). The development of catalysts that can catalyze hving polymerization in water was an important goal to achieve, especially for applications in biomedicine. In this context, two water-soluble ruthenium carbene complexes (3 and 4) have been reported that act as initiators for the living polymerization of water-soluble monomers in a quick and quantitative manner [29]. 

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