Organocatalysts supported

Polymer-supported organocatalysts have been used for cycloaddition of ketene, 127, to chloral, 128 [141]. Use of homo-acrylate polymers of cinchona alkaloids led to formation of the desired /Mactone (S)-130 with enantioselectivity up to... 

In addition, minor variation of the catalyst in combination with immobilization on a resin support gave an analogous recyclable solid-supported organocatalyst. Varying the derivatization method by trapping the a-amino nitrile intermediate with formic acid and acetic anhydride gives the crystalline formamides 19 in excellent yield and with high enantioselectivity. These features of this catalytic process have been demonstrated by results from the synthesis of r-tert-leucine (Scheme 14.8) [49]. 

Figure 4.5 Supported organocatalysts for the asymmetric reduction of imines.

For the preparation of soluble supported organocatalysts, noncross-linked polystyrene (PS) and poly(ethylene glycol) derivatives (PEG) are the most usual... 

Polymer-Supported Organocatalysts Based on Amino Acids 285... 

In summary, development of functional polymers that can act as efficient organocatalysts is at the origin of the application of modified polymers as reagents and catalysts in chemistry. To date, the most successful accomplishments have been carried out in the area of basic and acid catalysts. Not surprisingly, this area includes some of the most important industrial applications for supported reagents and catalysts. In general, the development of non-chiral polymer-supported organocatalysts is a field of research that involves both industrial and academic research. In many cases, it has been possible to demonstrate how the use of the... 

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