Development of New icroencapsulated Polymer-Supported Catalysts

聚合物催化剂因其易于加工、产品和催化剂易于分离、从经济角度以及在工业过程中的应用等优点得到了广泛的认可。然而，总的来说，聚合物催化剂存在制备困难、不稳定和活性低等缺点。为了解决这些问题，我们已经开发了一种新型的聚合物催化剂，称为微胶囊催化剂，这种催化剂制备容易，活性高，可回收和重复使用。开发了微胶囊四氧化三催化烯烃不对称双羟基化反应。采用微胶囊化技术，以四氧化三铯和ABS聚合物为原料，制备了催化剂。在大多数情况下，以高产率和高对映体过量获得了所需的二元醇。我们还开发了一种基于苯氧乙氧基甲基聚苯乙烯(PEM)的新型聚合物负载Os催化剂。催化剂系统不需要缓慢地添加烯烃，这是一个繁琐的过程。在有机合成中，钯催化剂在各种转化反应中有着广泛的用途，但它们价格昂贵，对空气敏感，在许多情况下无法回收。我们已经开发了三苯基膦钯，它已经成功地用于几个钯催化的反应。

The utility of polymer catalysts is now well-recognized because of their ease of workup and of separation of products and catalysts, from the economical point of view, and in application to industrial processes, etc. However, in general, polymer catalysts have some disadvantages such as difficult preparation, instability, and low activity. To address these issues, we have already developed new types polymer catalysts, named 'microencapsulated catalysts,' which are readily prepared, have high activity, and are recoverable and reusable.Catalytic asymmetric dihydroxylation of olefins using microencapsulated osmium tetroxide was developed. The catalyst was readily prepared from osmium tetroxide and an ABS polymer based on a microencapsulation technique. In most cases, the desired diols were obtained in high yields with high enantiomeric excesses.We have also developed a phenoxyethoxymethylpolystyrene (PEM)-based novel polymer-supported osmium catalyst. The catalyst system does not require a slow addition of olefins, which has been a tedious procedure. The catalyst was recovered quantitatively by simple filtration and reused without loss of activity.While palladium catalysts find wide-spread utility in a variety of transformations in organic synthesis, they are expensive, air-sensitive, and cannot be recovered in many cases. We have developed triphenylphosphine palladium, which has been successfully used in several palladium-catalyzed reactions.