Connecting Directed Ortho Metalation and Olefin Metathesis Strategies. Benzene-Fused Multiring-Sized Oxygen Heterocycles. First Syntheses of Radulanin A and Helianane
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,
Nickel-Catalyzed Amination of Aryl Sulfamates and Carbamates Using an Air-Stable Precatalyst
作者:Liana Hie、Stephen D. Ramgren、Tehetena Mesganaw、Neil K. Garg
DOI:10.1021/ol301847m
日期:2012.8.17
A facile nickel-catalyzed method to achieve the amination of synthetically useful arylsulfamates and carbamates is reported. Contrary to most Ni-catalyzed amination reactions, this user-friendly approach relies on an air-stable Ni(II) precatalyst, which, when employed with a mild reducing agent, efficiently delivers aminated products in good to excellent yields. The scope of the method is broad with
报道了一种简便的镍催化方法来实现合成有用的氨基磺酸芳基酯和氨基甲酸酯的胺化。与大多数 Ni 催化的胺化反应相反,这种用户友好的方法依赖于空气稳定的 Ni(II) 预催化剂,当它与温和的还原剂一起使用时,可以有效地以良好到优异的产率提供胺化产物。该方法的范围就两个偶联伙伴而言都是广泛的,并且包括杂环底物。
Lithiation of a Silyl Ether: Formation of an<i>ortho</i>-Fries Hydroxyketone
N‐diethylarylamide using CIPE‐assisted α‐silyl carbanions (CIPE=complex‐inducedproximityeffect) has been developed using a simple reagent combination of LDA (lithium diisopropylamide) and chlorosilane. A study of the mechanism, and the application of the procedure to an anionic Snieckus–Fries rearrangement for a highly efficient synthesis of the potent phosphatidylinositol 3‐kinase (PI3K) inhibitor LY294002
A phosgene‐ and metal‐free synthesis of O‐aryl carbamates is realized through a three‐component coupling of carbondioxide, amines and diaryliodoniumsalts. The reaction only requires a base as the promoter, providing access to a diverse array of O‐aryl carbamates in moderate to high yields with excellent chemoselectivity.
Palladium-catalysed ortho-arylation of carbamate-protected phenols
作者:Robin B. Bedford、Ruth L. Webster、Charlotte J. Mitchell
DOI:10.1039/b916724m
日期:——
The carbamate (–O2CNR2) function is an excellent directing group for palladium-catalysed direct arylation reactions giving both protected or free mono- or di-substituted phenols, as well as an example of a dibenzopyranone, depending on coupling partners (aryl iodides or diaryliodonium salts) and conditions.