A complex situation: Asymmetricepoxidation of conjugatedolefins was achieved at room temperature using ruthenium complex 1 as the catalyst and air as the oxidant to give epoxides in up to 95 % ee (see scheme). When the product was acid sensitive, the reaction was carried out at 0 °C under oxygen.
An Efficient Catalytic Asymmetric Epoxidation Method
作者:Zhi-Xian Wang、Yong Tu、Michael Frohn、Jian-Rong Zhang、Yian Shi
DOI:10.1021/ja972272g
日期:1997.11.1
This article describes a highly effective catalyticasymmetricepoxidation method for olefins using potassium peroxomonosulfate (Oxone, Dupont) as oxidant and a fructose-derived ketone (1) as catalyst. High enantioselectivies have been obtained for trans-disubstituted and trisubstituted olefins which can bear functional groups such as tributylsilyl ether, acetal, chloride, and ester. The enantiomeric
Asymmetric synthesis of optically active halohydrins and oxiranes by enantioselective reduction of prochiral α-haloketones with chirally modified lithium borohydride
作者:Kenso Soai、Takashi Yamanoi、Hitoshi Hikima
DOI:10.1016/0022-328x(85)87441-6
日期:1985.7
Prochiral α-haloketones are reduced enantioselectively with the asymmetric reducing system lithium borohydride N,N′-dibenzoylcystine /t-butyl alcohol to give the corresponding halohydrins with up to 86% enantiomeric excess, some of which are converted to optically active oxiranes.
Process for the ruthenium-catalysed epoxidation of olefins by means of hydrogen peroxide
申请人:Magerlein Wolfgang
公开号:US20060161011A1
公开(公告)日:2006-07-20
The present invention relates to a process for the epoxidation of olefins using catalysts based on ruthenium complexes in the presence of hydrogen peroxide.
本发明涉及一种利用基于钌配合物的催化剂在过氧化氢存在下对烯烃进行环氧化的方法。
Ruthenium-Catalyzed Asymmetric Epoxidation of Olefins Using H2O2, Part II: Catalytic Activities and Mechanism
tetra-substituted aromatic olefins with versatile functional groups can be epoxidized with this type of catalyst in good to excellent yields (up to 100 %) with moderate to good enantioselectivies (up to 84 % ee). Additive and solvent effects as well as the relative rate of reaction with different catalysts have been established. It is shown that the presence of weak organic acids or an electron-withdrawing