Synthesis and catalytic alcohol oxidation and ketone transfer hydrogenation activity of donor-functionalized mesoionic triazolylidene ruthenium(<scp>ii</scp>) complexes
作者:Manuela Delgado-Rebollo、Daniel Canseco-Gonzalez、Manuela Hollering、Helge Mueller-Bunz、Martin Albrecht
DOI:10.1039/c3dt53052c
日期:——
chloride/cymene spectator ligands and three analogous solvento complexes with MeCN spectator ligands were prepared and evaluated as catalystprecursors for direct base- and oxidant-free alcohol dehydrogenation, and for transferhydrogenation using basic iPrOH as a source of dihydrogen. In both catalytic reactions, the neutral/mono-cationic complexes with chloride/cymene spectator ligands performed better than
我们报告了包含不同供体取代基E(E = C:苯基阴离子; E = O:羧酸根,醇盐; E = N:杂环碳或氮上的吡啶)的各种C,E异构三唑基钌配合物的合成。这些供体功能的引入极大地促进了三唑的合成多功能性及其简便的制备途径。五种不同的以C,E为特征的络合物制备了具有氯/苏木精观众配体的三价钌配合中心,以及具有MeCN观众配体的三种类似的溶剂配合物,并将其评估为直接无碱和无氧化剂醇脱氢的催化剂前体,并使用碱性iPrOH作为二氢源进行了转移氢化。在这两个催化反应中,具有氯/苏木精观众配体的中性/单阳离子配合物的性能均优于溶剂钌配合物。供体的功能性对催化活性有进一步的深远影响。对于醇脱氢,C,C-双齿苯基-三唑基配体诱导最高的转化率,而羧酸盐或吡啶供体位点仅给出中等活性,或根本不给出活性。相反,当吡啶基供体基团通过杂环碳原子与三唑基亚烷基相连时,转移氢化是最有效的,对于环己酮转移氢化而言,提供高达1400
<i>N</i>-Mesityl-<i>C</i>-acylketenimines: 1,5-Sigmatropic Shifts and Electrocyclization to Quinolines
作者:V. V. Ramana Rao、Belinda E. Fulloon、Paul V. Bernhardt、Rainer Koch、Curt Wentrup
DOI:10.1021/jo9722562
日期:1998.8.1
undergo a 1,5-H shift to o-quinoid imines 12/13, followed by electrocyclization to dihydroquinolines 14 (unobserved) and 15 (observed by NMR). The latter are easily oxidized to alkylquinoline-3-carboxylates or quinoline-3-carboxamides 16 by atmospheric oxygen. Ab initio calculations on model compounds 18-23 predict an energy barrier of ca. 38 kcal mol(-)(1) (161 kJ mol(-)(1)) for the 1,5-H shift in N-(o-