Polymer-supported catalysis

B. Clapham, T.S. Reger and K.D. Janda, Polymer-supported Catalysis in Synthetic Organic Chemistry, Tetrahedron 57 4637-4662 2007. 

This review has shown that the analogy between P=C and C=C bonds can indeed be extended to polymer chemistry. Two of the most common uses for C=C bonds in polymer science have successfully been applied to P=C bonds. In particular, the addition polymerization of phosphaalkenes affords functional poly(methylenephosphine)s the first examples of macromolecules with alternating phosphorus and carbon atoms. The chemical functionality of the phosphine center may lead to applications in areas such as polymer-supported catalysis. In addition, the first n-conjugated phosphorus analogs of poly(p-phenylenevinylene) have been prepared. Comparison of the electronic properties of the polymers with molecular model compounds is consistent with some degree of n-conjugation in the polymer backbone. 

Selected Examples for Dendritic Polymer-supported Catalysis (see Tab. 7.2)... 

For general overviews on polymer-supported catalysis, see a) Chiral Catalyst Immohilization and Recycling (Eds. D. E. DeVos, I. F. ). Vankelecom,... 

Ford, W. T., J. Lee, and M. Tomoi, Mechanisms of Polymer-Supported Catalysis 3. Ion Exchange Limitations and Macroporous Polystyrene Supports, Macromolecules, 15,1246(1982). 

Tomoi, M., and W. T. For Mechanisms of Polymer-Supported Catalysis 1. Reaction of 1-Bromooctane with Aqueous Sodium Cyanide Catalyzed by Polystyrene-Bound Benzyltri-n-butyl-phosphonium Ion, /. ner. Chem Soc., 103,3821 (1981). 

Polymer-supported catalysis in synthetic organic chemistry 01T4737. 

One of the major benefits of polymer-supported catalysis is the recovery and the reuse of immobihsed catalysts, especially when dealing with chiral catalysts which can be extremely expensive [17]. Therefore effective separation methods are required [1]. However, one has to keep in mind that even the best separation technique can t overcome all the problems that can occur in polymer-sup-ported catalysis. For example, metal leaching is one major problem associated with the use and the recycHng of metal-based, polymer-supported catalytic systems and often the addition of fresh metal species to the recovered catalysts is... 

Some selected examples of hyperbranched polymer-supported catalysis are summarised in Table 4. Dendritic carbosilane structures are well suited for catalysis because they are relatively inert to common organometaUic reagents and their structures can be easily modified. For example, Frey and van Koten reported on the synthesis of a hyperbranched carbosilane, its fmctionaUsation with NCN moieties and the introduction of paUadium(II) sites into the structure [ 82 ]. This catalyst was introduced in aldol reactions and showed similar activity as the low molecular analogue. 

Clapham, B., Reger, T.S. and Janda, K.D. (2001) Polymer-supported catalysis in synthetic organic chemistry. Tetrahedron, 57, 4637 662. 

A number of strategies exist to incorporate and utilize noncovalent interactions in catalytically active structures. The simplest case, and most similar to traditional polymer-supported catalysis, would be to bind a catalyst through noncovalent interactions to the surface of the recyclable support (Scheme 1). 

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