Intramolecular trapping of an intermediate in the reduction of Imines by a hydroxycyclopentadienyl ruthenium hydride: Support for a concerted outer sphere mechanism
Intramolecular trapping of an intermediate in the reduction of Imines by a hydroxycyclopentadienyl ruthenium hydride: Support for a concerted outer sphere mechanism
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DOI：
10.1021/ja073370x
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发表时间：
2007-09-26
影响因子：
15
通讯作者：
Guzei, Ilia A.
中科院分区：
文献类型：
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作者：
Casey, Charles P.;Clark, Timothy B.;Guzei, Ilia A.
亚胺被[2，5-ph（2）-3，4-Tol（2）（eta（5）-C4 COH）]Ru（CO）（2）H（1）还原产生动力学稳定的钌胺络合物。研究了具有分子内胺的亚胺的还原，以区分内球和外球机制。1，4-（BnNH）-N-15（c-C_6 H_（10））=NBn（12）在甲苯-d（8）中被1还原，得到85%的[2，5-Ph-2- 3，4-Tol（2）（eta（4）-C_4CO）]（CO）（2）RuNHBn（c-C_6 H_（10））（NHBn）-N-15（16-RuN，N-15），由新形成的胺与钌中心的配位产生，和15%的捕获产物[2，5-Ph-2-3，4-Tol（2）（eta（4）-C4 CO）]（CO）（2）（RuNHBn）-N-15（c-C6 H10）NHBn（16-（RuN）-N-15，N），由分子内捕获胺的配位产生。这些结果为氢向亚胺的外层转移提供了支持，以生成配位不饱和中间体，该中间体可以被分子内胺捕获。相反的机理，需要在氢转移之前亚胺氮与钌配位，不能容易地解释捕获产物16-（RuN）-N-15，N的观察。
Reduction of imines by [2,5-ph(2)-3,4-Tol(2)(eta(5)-C4COH)]Ru(CO)(2)H (1) produces kinetically stable ruthenium amine complexes. Reduction of an imine possessing an intramolecular amine was studied to distinguish between inner sphere and outer sphere mechanisms. 1,4-(BnNH)-N-15(c-C6H10)=NBn (12) was reduced by 1 in toluene-d(8) to give 85% of [2,5-Ph-2-3,4-Tol(2) (eta(4)-C4CO)](CO)(2)RuNHBn(c-C6H10)(NHBn)-N-15 (16-RuN,N-15), resulting from coordination of the newly formed amine to the ruthenium center, and 15% of trapping product [2,5-Ph-2-3,4-Tol(2) (eta(4)-C4CO)](CO)(2)(RuNHBn)-N-15(c-C6H10)NHBn (16-(RuN)-N-15,N), resulting from coordination of the intramolecular trapping amine. These results provide support for an outer sphere transfer of hydrogen to the imine to generate a coordinatively unsaturated intermediate, which can be trapped by the intramolecular amine. An opposing mechanism, requiring coordination of the imine nitrogen to ruthenium prior to hydrogen transfer, cannot readily explain the observation of the trapping product 16-(RuN)-N-15,N.