An Osmium(III)/Osmium(V) Redox Couple Generating Os<sup>V</sup>(O)(OH) Center for <i>cis</i>-1,2-Dihydroxylation of Alkenes with H<sub>2</sub>O<sub>2</sub>: Os Complex with a Nitrogen-Based Tetradentate Ligand
作者:Hideki Sugimoto、Kazuhiro Kitayama、Seiji Mori、Shinobu Itoh
DOI:10.1021/ja309566c
日期:2012.11.21
2-dihydroxylation of alkenes catalyzed by osmium(VIII) tetroxide (OsO(4)) is a powerful method. However, OsO(4) is quite toxic due to its highly volatile and sublimable nature. Thus, the development of alternative catalysts for cis-1,2-dihydroxylation of alkenes is highly challenging. Our approach involves the use of a nitrogen-based tetradentate ligand, tris(2-pyridylmethyl)amine (tpa), for an osmium center to
对于 1,2-二醇的合成,由四氧化锇 (VIII) (OsO(4)) 催化的烯烃 cis-1,2-dihydroxylation 是一种有效的方法。然而,OsO(4) 由于其高度易挥发和可升华的性质而具有相当大的毒性。因此,开发用于烯烃顺式-1,2-二羟基化的替代催化剂极具挑战性。我们的方法涉及使用基于氮的四齿配体三(2-吡啶基甲基)胺(tpa)作为锇中心开发新的锇催化剂和过氧化氢(H(2)O(2))作为廉价的和环境无害的氧化剂。新的 Os-tpa 复合物作为一种非常有效的周转催化剂,用于水介质中各种烯烃的顺式选择性二羟基化(周转数~1000),并且 H(2)O(2) 氧化剂被正式定量并入产物中(100 % 原子效率)。参与催化循环的反应中间体已被分离出来,并在晶体学上表征为 [Os(III)(OH)(H(2)O)(tpa)](2+) 和 [Os(V)(O)(OH) (tpa)](2+)