Catalytic Intramolecular Hydroamination with a Bifunctional Iridium Pyrazolato Complex: Substrate Scope and Mechanistic Elucidation
Catalytic Intramolecular Hydroamination with a Bifunctional Iridium Pyrazolato Complex: Substrate Scope and Mechanistic Elucidation
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DOI：
10.1021/om301063n
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发表时间：
2012-11
期刊：
影响因子：
2.8
通讯作者：
Yohei Kashiwame;S. Kuwata;T. Ikariya
中科院分区：
文献类型：
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作者：
Yohei Kashiwame;S. Kuwata;T. Ikariya
具有官能团相容性的非活化氨基烯烃的催化分子内环化反应为合成含氮杂环提供了一条既经济又简明的原子路线，但仍是一个挑战。在这篇论文中，我们报道了我们最近开发的半夹心型Ir吡唑配合物催化分子内氢胺化反应的底物范围和反应机理。这种金属-配体双功能催化剂在温和的温度(50-110℃)下促进了各种伯氨基烯和仲氨基烯的氢胺化反应，没有氧化胺化等副反应。含酯、氰基、溴和羟基的仲氨基烯在保持这些官能团的情况下发生环化反应，而含烯丙基取代的氨基烯的反应具有很好的非对映选择性。催化剂优化表明，β位置上的质子响应性官能团对于催化剂的高效循环至关重要。动感..。
Catalytic intramolecular cyclization of nonactivated aminoalkene with functional group compatibility provides an atom-economical and concise route to valuable nitrogen-containing heterocycles yet remains a challenge. In this paper, we report the detailed substrate scope and mechanism of catalytic intramolecular hydroamination with a half-sandwich-type iridium pyrazolato complex we have recently developed. This metal–ligand bifunctional catalyst promoted the hydroamination of various primary and secondary aminoalkenes at mild temperatures (50–110 °C) without side reactions such as oxidative amination. Cyclization of secondary aminoalkenes containing ester, cyano, bromo, and hydroxy groups occurred with maintenance of these functional groups, while the reactions of aminoalkenes bearing allylic substituents proceeded with a perfect diastereoselectivity. Catalyst optimization revealed that the proton-responsive functional group at the position β to the metal is crucial to efficient catalytic turnover. Kinetic...