Enantioselective hydrogenation and transfer hydrogenation of bulky ketones catalysed by a ruthenium complex of a chiral tridentate ligand.
Enantioselective hydrogenation and transfer hydrogenation of bulky ketones catalysed by a ruthenium complex of a chiral tridentate ligand.
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DOI：
10.1002/chem.200801929
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发表时间：
2009-01
期刊：
影响因子：
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通讯作者：
M. Díaz-Valenzuela;Scott D Phillips;Marcia B France;Mary E. Gunn;Matthew L. Clarke
中科院分区：
文献类型：
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作者：
M. Díaz-Valenzuela;Scott D Phillips;Marcia B France;Mary E. Gunn;Matthew L. Clarke
报道了一类新型三齿钌配合物催化叔烷基酮对映选择性氢化的研究。与广泛研究的 [RuCl(2)(diphos)(di-primary amine)] 配合物相比，这种新型加氢催化剂可以平稳地还原这些反应性较低的大酮，其 ee 高达 94%。相同的催化剂体系还可以选择性地还原其他潜在有问题的底物，例如大体积杂环酮。对于加压氢化催化剂来说不同寻常的是，在转移氢化条件下可以获得类似的对映选择性。转移氢化比压力氢化稍慢，但这个缺点很容易克服，因为我们发现上述酮的微波加速转移氢化在约90℃下在20分钟内发生，并且具有与压力氢化系统中获得的相似的选择性。
A study on the enantioselective hydrogenation of tertiary alkyl ketones catalysed by a novel class of tridentate-Ru complex is reported. In contrast to the extensively studied [RuCl(2)(diphos)(di-primary amine)] complexes, this new class of hydrogenation catalyst smoothly reduces these less reactive bulky ketones with up to 94 % ee. The same catalyst system can also selectively reduce other potentially problematic substrates such as bulky heterocyclic ketones. Unusually for a pressure hydrogenation catalyst, similar enantioselectivity can be obtained under transfer hydrogenation conditions. The transfer hydrogenations are somewhat slower than the pressure hydrogenations, but this drawback is readily overcome, since we have discovered that a microwave accelerated transfer hydrogenation of the above ketones occurs within 20 min at about 90 degrees C with similar selectivity to that obtained in the pressure hydrogenation system.