Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Chem Asian J. 2013 Sep;8(9):2154-60. doi: 10.1002/asia.201300329. Epub 2013 May 7.
A simple protocol that uses Os(III)(OH)(H2O)(L-N4Me2)2 (1; L-N4Me2 = N,N'-dimethyl-2,11-diaza3.3pyridinophane) as a catalyst and H2O2 as a terminal oxidant for efficient cis-1,2-dihydroxylation of alkenes is presented. Unfunctionalized (or aliphatic) alkenes and alkenes/styrenes containing electron-withdrawing groups are selectively oxidized to the corresponding vicinal diols in good to excellent yields (46-99 %). In the catalytic reactions, the stoichiometry of alkene:H2O2 is 1:1, and thus the oxidant efficiency is very high. For the dihydroxylation of cyclohexene, the catalytic amount of 1 can be reduced to 0.01 mol % to achieve a very high turnover number of 5500. The active oxidant is identified as the Os(V)(O)(OH) species (2), which is formed via the hydroperoxide adduct, an Os(III)(OOH) species. The active oxidant 2 is successfully isolated and crystallographically characterized.
本文介绍了一种使用Os(III)(OH)(H2O)(L-N4Me2)2（1；L-N4Me2 = N,N'-二甲基-2,11-二氮杂3.3吡啶并菲）作为催化剂，H2O2 作为末端氧化剂，高效催化顺式 1,2-二羟基化烯烃的简单方法。未官能化（或脂肪族）烯烃和含有吸电子基团的烯烃/苯乙烯可以选择性地氧化成相应的顺式邻二醇，产率良好至优秀（46-99％）。在催化反应中，烯烃：H2O2 的化学计量比为 1:1，因此氧化剂效率非常高。对于环己烯的二羟基化，1 的催化量可以减少至 0.01 mol％，从而实现非常高的周转数 5500。活性氧化剂被确定为 Os(V)(O)(OH)物种（2），它是通过过氧化物加合物，即 Os(III)(OOH)物种形成的。活性氧化剂 2 已成功分离并进行了晶体结构表征。
