<i>para</i>
‐Selective C−H Borylation of (Hetero)Arenes by Cooperative Iridium/Aluminum Catalysis
作者:Lichen Yang、Kazuhiko Semba、Yoshiaki Nakao
DOI:10.1002/anie.201701238
日期:2017.4.18
para‐SelectiveC−H borylation of benzamides and pyridines has been achieved by cooperative iridium/aluminum catalysis. A combination of iridium catalysts commonly employed for arene C−H borylation and bulky aluminum‐based Lewis acid catalysts provides an unprecedented strategy for controlling the regioselectivity of C−H borylation to give variously substituted (hetero)arylboronates, which are versatile
ligand not only can facilitate the electrophilic aryl C–H rhodation but also can lower the olefin insertion barrier. Both electron-withdrawing and electron-donating directing groups such as -CONR2 and -NHAc could be employed in these reactions, which provides convenient routes toward a series styryl acetates, N-acetylindoles, and aryl methyl ketones.
尽管对过渡金属催化的Fujiwara–Moritani C–H型烯烃进行了广泛的研究,但这些转化中使用的烯烃仍主要限于活性丙烯酸酯和苯乙烯。富电子烯烃的选择性芳基CH烯化反应被认为是一个具有挑战性的问题。我们在本文中报道,简单且易于接近的缺电子的[CpRh(III)]和[Cp CF 3 Rh(III)](Cp CF 3 = C 5 Me 4 CF 3)配合物是富电子脱氢芳基化的有力催化剂烯烃,包括乙酸乙烯酯,酰胺和乙烯基醚。使用吸电子Cp或Cp CF 3配体代替特权Cp *(C5 Me 5)配体不仅可以促进亲电芳基C–H的铑基化,而且可以降低烯烃的插入势垒。在这些反应中都可以使用吸电子和供电子导向基团,例如-CONR 2和-NHAc,这提供了通向一系列乙酸苯乙烯酯,N-乙酰吲哚和芳基甲基酮的便捷途径。
Versatile Cp*Rh(III)-Catalyzed Selective <i>Ortho</i>-Chlorination of Arenes and Heteroarenes
The ortho- and monoselective Cp*Rh(III)-catalyzed chlorination of a broad range of benzenederivatives and electron-rich heterocycles under mild reaction conditions is reported. Inexpensive and commercially available N-chloro-imides could be used as chlorinating agents in as low as substoichiometric quantities. Furthermore, two different reaction protocols were developed to allow for the use of substrates
The present invention relates to modulators of muscarinic receptors. The present invention also provides compositions comprising such modulators, and methods therewith for treating muscarinic receptor mediated diseases.
Photocatalysis in aqueous micellar media has recently opened wide avenues to activate strong carbon–halide bonds. So far, however, it has mainly explored strongly reducing conditions, restricting the available chemical space to radical or anionic reactivity. Here, we demonstrate a controllable, photocatalytic strategy that channels the reaction of chlorinated benzamides via either a radical or a cationic
最近,水性胶束介质中的光催化为激活强碳卤键开辟了广阔的途径。然而,到目前为止,它主要探索了强烈的还原条件,将可用的化学空间限制为自由基或阴离子反应性。在这里,我们展示了一种可控的光催化策略,该策略通过自由基或阳离子途径引导氯化苯甲酰胺的反应,从而实现化学发散的 C-H 芳基化或N-脱烷基化。该催化系统在温和的条件下运行,亚甲基蓝作为光催化剂,蓝色 LED 作为光源。介绍了决定底物反应性、选择性和初步机理研究的因素。