Highly Effective Soluble Polymer-Supported Catalysts for Asymmetric Hydrogenation
Highly Effective Soluble Polymer-Supported Catalysts for Asymmetric Hydrogenation
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DOI：
10.1021/ja9837497
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发表时间：
1999-07
影响因子：
15
通讯作者：
Q. Fan;C. Ren;C. Yeung;Wenhao Hu;A. Chan
中科院分区：
文献类型：
--
作者：
Q. Fan;C. Ren;C. Yeung;Wenhao Hu;A. Chan
均相不对称催化是过去三十年来现代化学最重要的发展之一。已知许多手性催化剂表现出高活性和对映选择性。 1 然而，与大多数均相催化剂体系相关的一个主要问题是昂贵的手性催化剂的分离和回收。该问题的一个可能的解决方案是通过将催化剂固定在固体载体上或使用液液两相系统来“异质化”均相催化剂。近二十年来，不溶性聚合物负载催化剂的研究引起了广泛关注。 2,3 不幸的是，尽管具有易于分离的优点，但由于聚合物基质的限制，使用不溶性聚合物负载的催化剂会导致催化活性和立体选择性降低，从而导致活性位点的移动性和可及性受到限制。贵金属催化剂从聚合物载体中的浸出也是一个重要问题。近年来，聚合物负载非均相催化剂在不对称二羟基化、4环氧化、5加氢等领域取得了一些进展。 6
Homogeneous asymmetric catalysis is one of the most important developments in modern chemistry over the past three decades. Many chiral catalysts are known to exhibit high activities and enantioselectivities. 1 However, a major problem associated with most homogeneous catalyst systems is the separation and recycling of the expensive chiral catalyst. A possible solution to this problem is to “heterogenize” a homogeneous catalyst, either by anchoring the catalyst on a solid support or by using a liquid liquid two-phase system. Over the past two decades, the studies of insoluble polymer-supported catalysts have attracted much attention. 2,3 Unfortunately, despite the advantage of easy separation, the use of insoluble polymer-supported catalysts suffered from lowered catalytic activity and stereoselectivity due to the restriction of the polymer matrix which resulted in limited mobility and accessibility of the active sites. The leaching of the noble metal catalyst from the polymer support was also a significant problem. Recently, some progress on using polymer-supported heterogeneous catalysts has been made in the areas such as asymmetric dihydroxylation, 4 epoxidation, 5 and hydrogenation. 6