Mechanistically Driven Development of an Iron Catalyst for Selective <i>Syn</i>-Dihydroxylation of Alkenes with Aqueous Hydrogen Peroxide
作者:Margarida Borrell、Miquel Costas
DOI:10.1021/jacs.7b07909
日期:2017.9.13
to be resolved in the design of iron catalysts for olefin syn-dihydroxylation with potential utility in organic synthesis. Toward this end, in this work a novel catalyst bearing a sterically encumbered tetradentate ligand based in the tpa (tpa = tris(2-methylpyridyl)amine) scaffold, [FeII(CF3SO3)2(5-tips3tpa)], 1 has been designed. The steric demand of the ligand was envisioned as a key element to support
catalysts for efficient and selective alkene oxidation (epoxidation and cis‐dihydroxylation) employing hydrogenperoxide as oxidant. Complex [Fe(II)(Me,Me,HPyTACN)(CF3SO3)2] (7), was identified as the most efficient and selective cis‐dihydroxylation catalyst among the family. The high activity of 7 allows the oxidation of alkenes to proceed rapidly (30 min) at room temperature and underconditions where the
通式为[Fe(II)(R,Y,X PyTACN)(CF 3 SO 3)2 ]的铁络合物家族,其中R,Y,X PyTACN = 1‐ [2′‐(4‐Y‐6 -[X-吡啶基)甲基] -4,7-二烷基-1,4,7-三氮杂环壬烷,X和Y分别表示吡啶的4和6位上的基团,R表示在N-处的烷基取代基三氮杂双环壬烷环的4和N-7被证明是使用过氧化氢作为氧化剂进行有效且选择性的烯烃氧化(环氧化和顺式-二羟基化)的催化剂。络合物[Fe(II)(Me,Me,H PyTACN)(CF 3 SO 3)2 ](7)被认为是该家族中最有效和选择性最强的顺式-二羟基化催化剂。7的高活性使烯烃的氧化在室温下以及在不大量使用烯烃而仅是限制性试剂的条件下迅速进行(30分钟)。在3%(摩尔)的存在下7,2当量。H 2 O 2作为氧化剂,当量为15当量。在乙腈溶液中,水被烯烃顺式-二羟基化,其收率可能对于合成目的是令人感兴趣的。竞
Oxidation of alkenes with non-heme iron complexes: suitability as an organic synthetic method
作者:David Clemente-Tejeda、Francisco A. Bermejo
DOI:10.1016/j.tet.2014.10.037
日期:2014.12
In the course of a preliminary study to determine the preparative value and the synthetic applications of the non-heme iron(II) complexes Fe(bpmen)(OTf)(2) and Fe(tpa)(OTf)(2), in particular the oxidation of alkenes by using hydrogen peroxide as the terminal oxidant, we have found significant differences in catalyst behavior. After several attempts it was clear that the preparative relevance of the oxidation processes was linked to the concentration of the catalyst and optimal results were obtained when the concentration value was 5 mol %. At that concentration, the Fe(bpmen)(OTf)(2) catalyst mostly gave rise to mixtures of the epoxide and the trans-dihydroxylation products formed by water-assisted hydrolytic cleavage of the epoxides. Furthermore, the use of the tripodal ligand tpa led to cis dihydroxylation products. When deactivated olefins were used as substrates for the oxidation reaction, the cis-diols were obtained exclusively, although with modest conversions, regardless of the catalyst used. (C) 2014 Elsevier Ltd. All rights reserved.
A MILD AND STEREOSPECIFIC CONVERSION OF VICINAL DIOLS INTO OLEFINS VIA 2-METHOXY-1,3-DIOXOLANE DERIVATIVES
作者:Masayoshi Ando、Hiroshi Ohhara、Kahei Takase
DOI:10.1246/cl.1986.879
日期:1986.6.5
An efficient and practical method for the stereospecific synthesis of olefins from vicinal diols via the corresponding 2-methoxy-1,3-dioxolanes is reported.
报道了一种通过相应的 2-甲氧基-1,3-二氧戊环从邻二醇立体定向合成烯烃的有效且实用的方法。
Non-heme iron catalysis in C C, C–H, and CH2 oxidation reactions. Oxidative transformations on terpenoids catalyzed by Fe(bpmen)(OTf)2
作者:David Clemente-Tejeda、Alejandro López-Moreno、Francisco A. Bermejo
DOI:10.1016/j.tet.2013.02.013
日期:2013.4
The oxidation of terpene olefins with hydrogen peroxide in the presence of the non-hemo catalyst 5a afforded mixtures of epoxides whose composition was dependent upon the oxidation protocol used in each case. With terpenoid enones, the mixtures obtained evolved from clean epoxidation of α-ionone 23 to the clean allylic oxidation of damascone 28 due to the progressive deactivation of the electron density