Air‐Stable Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>‐EDTA‐Ni(0) as an Efficient Recyclable Magnetic Nanocatalyst for Effective Suzuki‐Miyaura and Heck Cross‐Coupling via Aryl Sulfamates and Carbamates
The synthesis of inexpensive and novel air‐stable Ni(0) nanoparticles immobilized on the EDTA‐modified Fe3O4@SiO2 nanocatalyst was investigated in Suzuki‐Miyaura and Heckcross‐couplingreactions. This catalytic system displayed a greatly improved substrate scope for the carbon–carbon bond formations starting from a wide range of green and economical electrophiles aryl and heteroaryl carbamates and
廉价且新颖的,稳定的,稳定在EDTA修饰的Fe 3 O 4 @SiO 2上的Ni(0)纳米颗粒的合成在Suzuki-Miyaura和Heck交叉偶联反应中研究了纳米催化剂。该催化体系通过在温和,操作简单的反应条件下通过高效方法,从广泛的绿色和经济亲电氨基甲酸酯和杂芳基氨基甲酸酯和氨基磺酸盐开始,显着改善了碳-碳键形成的底物范围。合成的多相催化剂还通过FT-IR,TEM,XRD,DLS,FE-SEM,UV-Vis,EDX,XPS,TGA,NMR,VSM,ICP和元素分析技术进行了全面表征。可以通过外部磁场容易地回收异质磁性纳米催化剂,并且在催化剂的沥滤可忽略不计并且活性没有实质性降低的情况下,至少七次重复用于接下来的反应至少七次。所有这些亮点使本协议变得有趣,
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
Ni‐catalyzed decarboxylative cross‐coupling of potassium polyfluorobenzoates with unactivated phenol and phenylmethanol derivatives is described. This novel transformation provides a practical and efficient protocol towards the synthesis of important polyfluorobiaryls and polyfluorinated diarylmethanes, and greatly enlarges the range of electrophiles utilized in decarboxylative coupling. Remarkably, preliminary
Pincer-Nickel-Catalyzed Cross-Coupling of Aryl Sulfamates with Arylzinc Chlorides
作者:Jian-Long Tao、Zhong-Xia Wang
DOI:10.1002/ejoc.201500987
日期:2015.9
The nickel N,N,N-pincer complex 2 was demonstrated to effectively catalyze the cross-coupling of arylsulfamates with arylzincchlorides under mild conditions. The reaction is suitable for a wide range of substrates, and tolerates various functional groups.
Nickel-Catalyzed Stille Cross Coupling of C–O Electrophiles
作者:John E. A. Russell、Emily D. Entz、Ian M. Joyce、Sharon R. Neufeldt
DOI:10.1021/acscatal.9b00744
日期:2019.4.5
Aryl sulfamates, tosylates, and mesylates undergo efficient Ni-catalyzed crosscoupling with diverse organostannanes in the presence of relatively unhindered alkylphosphine ligands and KF. The coupling is valuable for difficult bond constructions, such as aryl—heteroaryl, aryl—alkenyl, and aryl—alkynyl, using nontriflate phenol derivatives. A combination of experimental and computational studies implicates
在相对不受阻碍的烷基膦配体和 KF 存在下,芳基氨基磺酸盐、甲苯磺酸盐和甲磺酸盐可与多种有机锡烷进行有效的 Ni 催化交叉偶联。该偶联对于使用非三氟甲磺酸酯苯酚衍生物的困难的键构建很有价值,例如芳基-杂芳基、芳基-烯基和芳基-炔基。实验和计算研究的结合揭示了涉及 8 中心循环过渡态的不寻常的金属转移机制。由于 Ni(II)-氯化物中间体上有机锡烷的缓慢金属转移,该反应受到氯化物源的抑制。这些研究有助于解释为什么之前实现苯酚衍生物的 Ni 催化 Stille 偶联的努力不成功。