A General Strategy Toward Aromatic 1,2-Ambiphilic Synthons: Palladium-Catalyzed ortho-Halogenation of PyDipSi-Arenes
作者:Alexander S. Dudnik、Natalia Chernyak、Chunhui Huang、Vladimir Gevorgyan
DOI:10.1002/anie.201004426
日期:2010.11.8
A general and efficient strategy to synthesize 1,2‐ambiphilic aromatic and heteroaromatic synthons from haloarenes has been developed. The method involves installation of the PyDipSi directing group, and subsequent palladium‐catalyzed directed ortho‐halogenation of aryl silanes (see scheme; Py=2‐pyridyl). The usefulness of these 1,2‐ambiphilic building blocks was shown in their participation as both
The Pyridyldiisopropylsilyl Group: A Masked Functionality and Directing Group for Monoselective ortho-Acyloxylation and ortho-Halogenation Reactions of Arenes
作者:Chunhui Huang、Natalia Chernyak、Alexander S. Dudnik、Vladimir Gevorgyan
DOI:10.1002/adsc.201000975
日期:2011.5
removable and modifiable silicon‐tethered pyridyldiisopropylsilyl directing group for CH functionalizations of arenes has been developed. The installation of the pyridyldiisopropylsilyl group can efficiently be achieved via two complementary routes using easily available 2‐(diisopropylsilyl)pyridine (5). The first strategy features a nucleophilic hydride substitution at the silicon atom in 5 with aryllithium
开发了一种新型、易于去除和可修饰的硅系吡啶基二异丙基甲硅烷基导向基团,用于芳烃的 C - H 官能化。使用容易获得的 2-(二异丙基甲硅烷基)吡啶 ( 5 ),可以通过两条互补路线有效地实现吡啶基二异丙基甲硅烷基的安装。第一种策略的特点是用由相应的芳基溴化物或碘化物原位产生的芳基锂试剂在5中的硅原子上进行亲核氢化物取代。第二条较温和的路线利用了5碘化物和芳基碘化物之间高效的室温铑 (I) 催化交叉偶联反应。后一种方法可用于制备各种具有多种官能团的吡啶基二异丙基甲硅烷基取代的芳烃,包括与有机金属试剂不相容的官能团。吡啶基二异丙基甲硅烷基导向基团可以实现高效、区域选择性的钯(II)催化的单邻酰氧基化和各种芳香族化合物的邻卤化。最重要的是,酰氧基化和卤化产物中的硅系导向基团可以轻松去除或有效转化为一系列其他有价值的官能团。这些转化包括质子、氘代、卤代、硼代和炔基脱甲硅烷基化,以及导向基团向羟基官