Ruthenium-Catalyzed Asymmetric Epoxidation of Olefins Using H2O2, Part I: Synthesis of New ChiralN,N,N-Tridentate Pybox and Pyboxazine Ligands and Their Ruthenium Complexes
作者:Man Kin Tse、Santosh Bhor、Markus Klawonn、Gopinathan Anilkumar、Haijun Jiao、Christian Döbler、Anke Spannenberg、Wolfgang Mägerlein、Herbert Hugl、Matthias Beller
DOI:10.1002/chem.200501261
日期:2006.2.20
The synthesis of chiral tridentate N,N,N-pyridine-2,6-bisoxazolines 3 (pybox ligands) and N,N,N-pyridine-2,6-bisoxazines 4 (pyboxazine ligands) is described in detail. These novel ligands constitute a useful toolbox for the application in asymmetric catalysis. Compounds 3 and 4 are conveniently prepared by cyclization of enantiomerically pure alpha- or beta-amino alcohols with dimethyl pyridine-2,6-dicarboximidate
详细描述了手性三齿N,N,N-吡啶-2,6-双恶唑啉3(pyboxbox配体)和N,N,N-吡啶-2,6-双恶嗪4(pyboxazine配体)的合成。这些新的配体构成了用于不对称催化的有用工具箱。化合物3和4可方便地通过对映体纯的α-或β-氨基醇与二甲基吡啶-2,6-二羧酸二亚氨基酯环化而制备。相应的钌配合物是有效的不对称环氧化催化剂,并以高收率制备并通过光谱学手段充分表征。这些钌络合物中的四个已通过X射线晶体学表征。哒嗪络合物[2,6-双-[(4S)-4-苯基-5,6-二氢-4H- [1,3]恶嗪基]吡啶](吡啶-2,6的分子结构首次) -二羧酸四硼酸酯)钌(S)-2 aa,