Catalytic asymmetric epoxidation of alpha,beta-unsaturated ketones promoted by lanthanoid complexes
Catalytic asymmetric epoxidation of alpha,beta-unsaturated ketones promoted by lanthanoid complexes
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DOI：
10.1021/ja964037o
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发表时间：
1997-03-05
影响因子：
15
通讯作者：
Shibasaki, M
中科院分区：
文献类型：
--
作者：
Bougauchi, M;Watanabe, S;Shibasaki, M
催化不对称环氧化反应是最重要的不对称反应之一。1、1980年夏普莱斯等人提出的。报道了烯丙醇的化学计量不对称环氧化反应，2a，该方法后来被改进为催化过程。2b另外，Jacobsen等人，3a Katsuki等人，3b和Mukaiyama等人独立报道了使用Salen-锰络合物催化非官能化烯烃的不对称环氧化反应。与这些成功的成就形成鲜明对比的是，还没有开发出具有广泛普遍性的有效的烯酮催化不对称环氧化反应。5最近，Enders和他的同事报道了一种非常令人印象深刻和实用的烯酮不对称环氧化反应，该反应使用化学计量的N-甲基伪麻黄碱作为手性来源。6在这篇论文中，我们报道了一种高效的稀土配合物催化烯酮的不对称环氧化反应，这是适用于各种烯类的催化过程的第一个例子。我们成功地开发了几种异双金属手性催化剂，如LnM3三(联萘氧化物)络合物(LnMB)，AlMbis(联萘氧化物)络合物(AMB)和Gambis(联萘氧化物)络合物(Gamb)(Ln)稀土，M)碱金属，A)铝，Ga)镓，B)BINOL(1)或其衍生物。其中，LSb，Alb和GaSb(L)镧，S)钠，L)锂)已被发现对催化不对称Michael反应非常有用。7我们设想这些手性催化剂将用于叔丁基氢过氧化氢(Tbhp)和异丙苯等过氧化氢催化烯酮不对称环氧化。
Catalytic asymmetric epoxidations are one of the most important asymmetric processes. 1 In 1980 Sharpless et al. reported a stoichiometric asymmetric epoxidation of allylic alcohols, 2a a method which was later improved to a catalytic process. 2b Moreover, catalytic asymmetric epoxidations of unfunctionalized olefins using salen-manganese complexes have been reported independently by Jacobsen et al., 3a Katsuki et al., 3b and Mukaiyama et al. 3c, 4 In striking contrast to these successful achievements, an efficient catalytic asymmetric epoxidation of enones with broad generality has not been developed. 5 Quite recently, Enders and co-workers reported a very impressive and practical asymmetric epoxidation of enones using a stoichiometric amount of N-methylpseudoephedrine as a chiral source. 6 In this Communication we report an efficient catalytic asymmetric epoxidation of enones using lanthanoid complexes, which is the first example of a catalytic process applicable to various enones.We have succeeded in developing several kinds of heterobimetallic chiral catalysts such as LnM3tris (binaphthoxide) complexes (LnMB), AlMbis (binaphthoxide) complexes (AMB), and GaMbis (binaphthoxide) complexes (GaMB)(Ln) lanthanoid, M) alkali metal, A) aluminium, Ga) gallium, B) BINOL (1) or its derivatives). 7 Among them, LSB, ALB, and GaSB (L) lanthanum, S) sodium, L) lithium) have been found to be very useful for catalytic asymmetric Michael reactions. 7 We envisioned that these chiral catalysts would be useful for the asymmetric epoxidation of enones using hydroperoxides such as tert-butyl hydroperoxide (TBHP) and cumene