Catalytic Organic Synthetic Processes in Water: Zero-Emission Switching

由于对有害和消耗资源的溶剂废物的环境关注日益增加，水中有机转化的化学目前正经历非常迅速的增长。另一方面，固定化试剂的发展因其实用优势而引起了人们的极大兴趣。有充分的理由相信，在水介质中表现出高催化活性的固定化催化剂为完成许多有机反应提供了一种可行的清洁替代方法。我们研究了两亲性树脂负载的三芳膦-钯配合物的设计和制备，该配合物与聚乙二醇-聚苯乙烯接枝共聚物（PEG-PS树脂）结合，在温和的反应条件下，在水介质中与各种亲核试剂的烯丙酸酯的烯丙基取代反应中表现出很高的催化活性。作为开发这些催化剂广泛应用的一部分，我们还成功地研究了钯催化的交叉偶联反应和钯催化的水中羟基羰基化反应。

Owing to increasing environmental concerns about harmful and resource-consuming solvent waste, the chemistry of organic transformations in water is presently undergoing very rapid growth. On the other hand, development of immobilized reagents has been attracting significant interest for their practical advantages. There is good reason to believe that immobilized catalysts exhibiting high catalytic activity in aqueous media offer a viable clean alternative to more traditional methods of accomplishing many organic reactions. We have examined design and preparation of amphiphilic resin-supported triarylphosphine-palladium complexes bound to a polyethylene glycol-polystyrenegraft copolymer (PEG-PS resin) which exhibit high catalytic activity in allylic substitution reactions of allyl acetates with various nucleophiles in aqueous media under mild reaction conditions. As a part of our efforts to develop the wide utility of these catalysts, the palladium-catalyzed cross-coupling reaction and palladium-catalyzed hydroxycarbonylation in water were also successfully examined.