A Neutral RuII Hydride Complex for the Regio- and Chemoselective Reduction of N-Silylpyridinium Ions
A Neutral RuII Hydride Complex for the Regio- and Chemoselective Reduction of N-Silylpyridinium Ions
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DOI：
10.1002/chem.201705899
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发表时间：
2018-04-11
影响因子：
4.3
通讯作者：
Oestreich, Martin
中科院分区：
文献类型：
--
作者：
Baehr, Susanne;Oestreich, Martin
详细的实验分析的1，4-选择性还原吡啶与氢硅烷催化的配位不饱和钌-II硫醇配合物的报告。先前建议的中间体，N-甲硅烷基吡啶离子和中性钌-II氢化物，已独立合成，并确实参与催化循环。静止状态不是最初用作催化剂的阳离子Ru-II络合物，而是其吡啶配位同系物。所有Ru-II络合物，包括由氢硅烷活化产生的络合物，彼此处于平衡。N-甲硅烷基化的1，4-二氢吡啶与阳离子Ru-II络合物一起转化回相应的N-甲硅烷基吡啶鎓离子和中性Ru-II氢化物（逆氢化硅烷化），随后进一步逆反应成氢硅烷和阳离子络合物的吡啶加合物。这些步骤证明了转换的总体可逆性。
A detailed experimental analysis of the 1,4-selective reduction of pyridine with hydrosilanes catalyzed by a coordinatively unsaturated Ru-II thiolate complex is reported. The previously suggested intermediates, N-silylpyridinium ions and a neutral Ru-II hydride, have been independently synthesized and do indeed participate in the catalytic cycle. The resting state is not the cationic Ru-II complex initially used as the catalyst but its pyridine-coordinated congener. All Ru-II complexes, including the one resulting from hydrosilane activation, are in equilibrium with each other. The N-silylated 1,4-dihydropyridine together with the cationic Ru-II complex convert back into the corresponding N-silylpyridinium ion and the neutral Ru-II hydride (retro-hydrosilylation), followed by further backward reaction into the hydrosilane and the pyridine adduct of the cationic complex. These steps prove the overall reversibility of the transformation.