Preparation of New Metallocene Ligands with Combined Chiralities and Their Application to Catalytic Asymmetric Synthesis

在催化量为Cu(OTf)_2和Sc(OTf)_3的Lewis酸存在下，叠氮三甲基硅烷在CH_2Cl_2中处理（R，R）-1,2-二[（1-乙酰氧基）苯基甲基]二茂铁，得到了主要的（R，R）-异构体和次要的（R，S）-异构体。光学活性的二茂铁基二叠氮化物与LiAlH_4还原后可转化为二茂铁基二胺，分离出稳定的二酰基酰胺和二乙酰胺。二茂铁二胺和二胺作为配体用于钌配合物催化芳基酮的不对称转移加氢反应，二茂铁二胺配合物产率高达75%。平面手性邻恶唑啉取代甲酰基二茂铁的双酚偶联反应得到了1,2-二茂铁-1,2-二醇三种非对映体的混合物；(R, R): (S, S): (R, S) = 24:31:45。用柱层析法分离得到了树的非对映体，并用x射线衍射分析证实了它们的立体化学性质。用s-BuLi还原Sm(OTf)_3制得的二价三酸钐Sm(OTf)_2对（R，R）异构体的选择性有50%的提高。Yb(OTf)_3与（R，R）-二茂铁二醇的结合是3-酰基氧唑烷酮与环戊二烯不对称Diels-Alder反应的良好催化剂，其内合产物的ee可达80%。

The treatment of (R,R)-1,2-bis[(1-acetoxy)phenylmethyl]ferrocene with azidotrimethylsilane in CH_2Cl_2 in the presence of a catalytic amount of a Lewis acid such as Cu(OTf)_2 and Sc(OTf)_3, gave, the major (R,R)-isomer as major product with a minor meso-(R,S)-isomer. The optically active ferrocenyl diazide could be converted into the corresponding ferrocenyl diamine by reduction with LiAlH_4, and its ditosylamide and diacetamide were isolated as stable compounds. The ferrocenyl diamine and diamides were applied to ligands for the ruthenium complex catalyzed asymmetric transfer hydrogenation of aryl ketones and the complex with ferrocenyl diamine gave 1-arylethanols in good yields with up to 75% ee.The pinacol coupling reaction of planar chiral ortho-oxazoline substituted formylferrocene by SmI_2 gave a mixture of three diastereomers of 1,2-diferrocenyl-1,2-diols; (R,R):(S:S):(R:S)=24:31:45. The tree diastereomers could be isolated by column chromatography, and their stereochemistries were confirmed by X-ray diffraction analysis. The use of divalent samarium triflate "Sm(OTf)_2", which was prepared by reduction of Sm(OTf)_3 with s-BuLi, remarkably improved the selectivity for the (R,R) isomer with 50% de. The combination of Yb(OTf)_3 and the (R,R)-ferrocenyl diol was revealed to be a good catalyst for the asymmetric Diels-Alder reaction of 3-acyloxazolidinone with cyclopentadiene, and the endo adduct was produced in up to 80% ee.