A Convenient Alumination of Functionalized Aromatics by Using the Frustrated Lewis Pair Et<sub>3</sub>Al and TMPMgCl⋅LiCl
作者:Andreas Unsinn、Stefan H. Wunderlich、Anukul Jana、Konstantin Karaghiosoff、Paul Knochel
DOI:10.1002/chem.201301869
日期:2013.10.18
straightforward and efficient alumination of functionalizedarenes by using the frustrated Lewis pair Et3Al and TMPMgCl⋅LiCl (TMP=2,2,6,6‐tetramethylpiperidyl) has been developed. In particular, halogenated electron‐rich aromatics can be smoothly functionalized by using the frustrated Lewis pair Et3Al and TMPMgCl⋅LiCl. Compared with previously described alumination methods, this procedure avoids extensive cooling
Unified Protocol for Fe-Based Catalyzed Biaryl Cross-Couplings between Various Aryl Electrophiles and Aryl Grignard Reagents
作者:Lei Wang、Yi-Ming Wei、Yan Zhao、Xin-Fang Duan
DOI:10.1021/acs.joc.9b00151
日期:2019.5.3
Ti(OEt)4/PhOM enabled a highly general iron-based catalyst system, which could efficiently catalyze the biaryl coupling reaction between various electrophiles (I, Br, Cl, OTs, OCONMe2, OSO2NMe2) and common or functionalized aryl Grignardreagents with high functional group tolerance. Selective couplings of aryl iodides and bromides over the corresponding oxygen-based electrophiles have been achieved, and
Palladium Catalyzed C–H Functionalization of <i>O</i>-Arylcarbamates: Selective <i>ortho</i>-Bromination Using NBS
作者:Alex John、Kenneth M. Nicholas
DOI:10.1021/jo300713h
日期:2012.7.6
cis-coordination of the amine. However, the amine adducts failed to undergo ortho-amination (C–N bond formation) under varied reaction conditions. Notably, the palladacycle 1d was found to react efficiently with N-iodosuccinimide (NIS) to yield the ortho-iodinated carbamate, 1e. More significantly, this reaction can be extended to a palladium-catalyzed ortho C–H bromination of aryl-O-carbamates even at 5 mol %
通过使各自的氨基甲酸酯与Pd(OAc)2在酸,CF 3 CO 2 H,CF 3 SO 3 H和p -TsOH存在下反应,合成了一系列衍生自O-苯基氨基甲酸酯的环金属化钯配合物。观察到palladacycles能配位胺和富电子的苯胺,但不能配位磺酰胺或羧酰胺。通过NMR光谱法(NOE)分析palladacycle 2b(2b · t Bu-NH 2)的t Bu-NH 2加合物显示出一种顺式-胺的配位。但是,在不同的反应条件下,胺加合物均无法进行邻氨基化(C–N键形成)。值得注意的是,发现palladacycle 1d与N-碘琥珀酰亚胺(NIS)有效反应,生成邻碘代氨基甲酸酯1e。更重要的是,即使在使用N-溴代琥珀酰亚胺(NBS)的Pd(OAc)2负载为5 mol%的情况下,该反应也可以扩展为钯催化的芳基-O-氨基甲酸酯的邻位C-H溴化反应。
Pd(<scp>ii</scp>) catalyzed ortho C–H iodination of phenylcarbamates at room temperature using cyclic hypervalent iodine reagents
作者:Xiuyun Sun、Xia Yao、Chao Zhang、Yu Rao
DOI:10.1039/c5cc02533h
日期:——
The first example to access ortho iodinated phenols using cyclic hypervalent iodine(iii) reagents through palladium(ii) catalyzed C–H activation has been developed via weak coordination. The reaction showed excellent regioselectivity, reactivity and good functional group tolerance. A unique mechanism was proposed.
nickel-catalyzed cyanation of phenol derivatives with metal-free cyanating agents, aminoacetonitriles, is described. A nickel-based catalytic system consisting of a unique diphosphine ligand such as dcype or dcypt enables the cyanation of versatile phenol derivatives such as aryl carbamates and aryl pivalates. The use of aminoacetonitriles as a cyanating agent leads to an environmentally and easy-to-use method