Asymmetric Hydrosilylation by Means of Homogeneous Catalysts with Chiral Ligands
Asymmetric Hydrosilylation by Means of Homogeneous Catalysts with Chiral Ligands
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手性配体均相催化剂的不对称氢化硅烷化
DOI：
10.1007/978-94-010-1199-0_3
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
M. Kumada
中科院分区：
文献类型：
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作者：
I. Ojima;Keiji. Yamamoto;M. Kumada
长期以来，不对称合成一直受到人们的关注，许多类型的化学计量反应已经被探索出来。然而，手性试剂最有效的用途是用作催化剂。手性过渡金属配合物催化的立体选择性反应具有广阔的应用前景。一般来说，一种有吸引力的“均相催化不对称反应”的方法主要是通过发展光活性膦作为配体的制备路线而成为可能的。然而，关键问题之一是如何开发一种手性配体，使特定反应的催化剂具有尽可能高的立体选择性。目前，用于此目的的手性配体的选择是相当经验性的。从这个意义上说，一些最令人兴奋的不对称合成已经在使用可溶铑(I)配合物与手性膦配体催化前手性烯烃的不对称加氢方面取得了进展。Knowles等人发现，使用铑配合物与(R)-o-苯基环己基甲基膦或(R)-双（o-苯基苯基膦）乙烷催化加氢，α-酰基氨基甲酸的相应氨基酸衍生物具有80 - 95%的对映体过量（% e.e.）。Kagan和Dang[3]用(-)-2,3- o -异丙基-2,3-二羟基-1,4-双（二苯基膦）丁烷（DIOP）作为配体的铑催化剂也得到了类似的结果。
Asymmetric synthesis has acquired much interest for a long time, and many types of stoichiometric reactions have been explored [1]. However, the most effective use of chiral reagents is their use as catalysts. Stereoselective reactions catalyzed by chiral transition metal complexes may be of great promise. In general, an attractive approach to ‘homogeneously catalyzed asymmetric reactions’ has been made possible mainly by the development of preparative routes to optically active phosphines as ligands. Yet, one of the crucial problems is how to develop a chiral ligand which will enable the catalyst for a particular reaction to be as efficient in stereoselectivity as possible. At the present time the choice of the chiral ligand for this purpose is quite empirical. In this sense, some of the most exciting developments in asymmetric synthesis have been made on the catalytic asymmetric hydrogenation of prochiral olefins using soluble rhodium(I) complexes with chiral phosphine ligands. Knowles et al. [2] have found that the catalytic hydrogenation of α-acylamidocinnamic acids affords the corresponding amino acid derivatives with 80–95 percent enantiomeric excess (% e.e.) using rhodium complexes with (R)-o-anisylcyclohexylmethylphosphine or (R)-bis(o-anisylphenylphosphino)ethane. Similar results have been obtained by Kagan and Dang [3] by the use of a rhodium catalyst with (—)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (DIOP) as ligand.