原位制备的铁配合物催化烯烃选择性环氧化

Selective Epoxidation of Olefins Catalyzed by in Situ Prepared Iron(Ⅱ) Complex

制备了配体2-(2-吡啶基)-噁唑啉。该含氮配体能够在乙腈溶液中与三氟甲磺酸亚铁和其它辅助配体原位形成具有催化活性的六配位金属亚铁配合物。量子化学计算表明配体上的氮原子而非氧原子与铁配位。研究表明,以H_2O_2为氧化剂,该金属配合物能够在乙腈溶液中高活性地催化末端芳香烯烃和脂肪烯烃的环氧化反应;该反应条件温和、迅速、选择性好并且适用底物范围宽泛。辅助配体、溶剂和氧化剂等因素对反应的活性和选择性影响很敏感,文中对这些影响进行了较详细的研究。

A ligand of 2-(2-pyridyl)-oxazoline (Pyrox) was prepared. The complex of containing Iron(Ⅱ)trifluomethanesulfonate, Pyrox and another auxiliary ligand can be in situ formed in acetonitrile solution. Quantum chemistry calculations showed that the nitrogen rather than oxygen atom on the Pyrox coordinates with Iron. It was found the terminal aromatic and aliphatic olefins could be efficiently epoxidized with H2O2 catalyzed by this Iron complex in acetonitrile at room temperature. The reaction with good selectivity was rapid, mild and in an wide range of substrates. The influences of axial ligands, solvents and oxidants are sensitive to the activity and selectivity of the reaction, and the effects have been investigated in detail.