ASYMMETRIC CATALYTIC REDUCTION WITH TRANSITION-METAL COMPLEXES .2. ASYMMETRIC CATALYSIS BY A SUPPORTED CHIRAL RHODIUM COMPLEX
ASYMMETRIC CATALYTIC REDUCTION WITH TRANSITION-METAL COMPLEXES .2. ASYMMETRIC CATALYSIS BY A SUPPORTED CHIRAL RHODIUM COMPLEX
复制标题
DOI：
10.1021/ja00806a015
复制
发表时间：
1973-01-01
影响因子：
15
通讯作者：
KAGAN, HB
中科院分区：
文献类型：
--
作者：
DUMONT, W;POULIN, J;KAGAN, HB
用梅里菲尔德树脂制备了一种与可溶性Rh（I）-二异丙基-2，3-二羟基-1，4-二（二苯基膦基）丁烷（1）密切相关的不溶性手性聚合物负载铑配合物。这种不溶性体系（悬浮在苯中）催化α-乙基苯乙烯和甲基丙烯酸酯的不对称氢化反应，其催化效率比在溶液中低得多，而乙醇抑制了这种催化作用。相比之下，可溶性和不溶性的催化体系对于酮（苯乙酮、甲基苄基酮、异丁酰苯）的不对称氢化硅烷化都非常有效。对于给定的酮，光学产率强烈地取决于所使用的硅烷。二氢硅烷（二苯基硅烷、苯基甲基硅烷、-萘基苯基硅烷）总是比一氢硅烷（三乙基硅烷、三乙氧基硅烷、三苯基硅烷）好。光学产率高达58%。在所有情况下，不溶性催化剂都可以过滤并容易地重复使用。不对称合成中最新和最重要的进展之一是可溶性手性催化剂的使用。可溶性催化剂比非均相催化剂具有更好的限定性，并且在这种络合物中，为了优化不对称合成的化学产率和光学产率，通常容易广泛地改变催化活性中心的空间和电子位置。
An insoluble chiral polymer-supported rhodium complex closely relatedto the soluble Rh (I)-diop com-plex (diop= 2, 3-0-isopropylidene-2, 3-dihydroxy-l, 4-bis (diphenylphosphino) butane (1)) was prepared using a Merrifield resin. This insoluble system (suspended in benzene) catalyzes the asymmetric hydrogenation of a-ethylstyrene and methyl atrópatewith a much lower efficiency than in solution, and ethanol inhibits the catalysis. In contrast, both catalytic systems, soluble and insoluble, are very efficient for asymmetric hydrosilylation of ketones (acetophenone, methyl benzyl ketone, isobutyrophenone). For a given ketone, the optical yield strongly depends upon the silane used. Dihydrosilanes (diphenylsilane, phenylmethylsilane,-naphthylphenylsilane) are always better than monohydrosilanes (triethylsilane, triethoxysilane, triphenylsilane). Optical yields up to 58% were obtained. In all cases, the insoluble catalyst can be filtered and easily reused. ne of the most recent and important advances in asymmetric synthesis is the use of a soluble chiral catalyst. Soluble catalysts can be better defined than the heterogeneous ones, and in such complexes it is often easy to vary widely the steric and electronic en-vironment of the catalytically active site in order to optimize both the chemicaland optical yields of an asymmetric synthesis.