Rhenium-catalyzed C-H and C-C bond activation
Rhenium-catalyzed C-H and C-C bond activation
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DOI：
10.1002/anie.200605228
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Horino, Yoshikazu
中科院分区：
文献类型：
--
作者：
Horino, Yoshikazu
原子经济和环境友好的化学反应原理引起了人们对基于碳氢键功能化的方法的极大兴趣。[1]然而，到目前为止，关于碳-碳单键功能化的报道要少得多。考虑到催化剂在碳-碳键活化过程中必须克服的最大立体障碍，这并不令人意外。在这一领域的早期工作中，Tipper和Bergman研究了化学计量比的C±C键激活，[2]随后，设计出了各种解决催化C±C键激活的策略。然而，到目前为止，还没有真正通用的方法，这一领域仍然是有机合成的一个主要挑战。[3]到目前为止开发的系统中，大多数都受益于环应变、[4]螯合辅助[5]或金属醇盐的形成[6]，以允许C±C单键的选择性断裂。最近库尼诺布和高井关于Re(I)催化的通过直接C±H活化形成C±C键的报告说明了一种独特的反应活性模式。以[{REBR(CO)3(THF)}2]为催化剂，乙二胺1与乙炔反应生成了具有良好区域选择性的吲衍生物5(方案1)。[7]从活性催化剂上去掉一个可能导致空位配位的CO配体，可提高反应的产率。
The principles of atom economy and environmentally benign chemical reactions have generated substantial interest in the development of methods based on the functionalization of carbon–hydrogen bonds.[1] To date, however, there have been far fewer reports on the functionalization of carbon–carbon single bonds. This is no surprise given the paramount steric obstacles a catalyst must overcome along the path to carbon–carbon bond activation. In early work in this area, Tipper and Bergman studied stoichiometric CÀC bond activation,[2] and subsequently, a variety of strategies addressing catalytic CÀC bond activation have been devised. To date, however, no truly general methods exist, and this area remains a major challenge for organic synthesis.[3] Of the systems developed thus far most have benefitted from ring strain,[4] chelation assistance,[5] or the formation of metal alcoholates to β-alkyl elimination [6] to allow for the selective cleavage of the CÀC single bond.Recent reports by Kuninobu and Takai on the rhenium (I)-catalyzed CÀ C bond formation by direct CÀH activation illustrate a unique mode of reactivity. The reaction of aldimine 1 with acetylenes using [{ReBr (CO) 3 (thf)} 2] as the catalyst afforded indene derivative 5 with excellent regioselectivity (Scheme 1).[7] The yield of the reaction was improved when a CO ligand was removed from the active catalyst which presumably results in a vacant coordi-