Osmium(III) and Osmium(V) Complexes Bearing a Macrocyclic Ligand: A Simple and Efficient Catalytic System for<i>cis</i>-Dihydroxylation of Alkenes with Hydrogen Peroxide
作者:Hideki Sugimoto、Kenji Ashikari、Shinobu Itoh
DOI:10.1002/asia.201300329
日期:2013.9
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
一个简单的协议,它使用[Os III(OH)(H 2 O)(L -N 4 Me 2)](PF 6)2(1 ; L- N 4 Me 2 = N,N'-二甲基-2,11 ‐diaza [3.3](2,6)pyridinophane)作为催化剂,H 2 O 2作为有效顺式的末端氧化剂介绍了烯烃的1,2-二羟基化反应。含有吸电子基团的未官能化(或脂肪族)烯烃和烯烃/苯乙烯被选择性氧化成相应的邻位二醇,收率良好至极佳(46–99%)。在催化反应中,烯烃:H 2 O 2的化学计量为1:1,因此氧化效率非常高。对于环己烯的二羟基化,可以将1的催化量降低至0.01 mol%,以实现5500的极高周转率。活性氧化剂被鉴定为Os V(O)(OH)种类(2)。通过氢过氧化物加合物形成的Os III(OOH)物种。活性氧化剂2 已成功分离并进行了晶体学表征。