Isolation of Cp*Co<sup>III</sup>
-Alkenyl Intermediate in Efficient Cobalt-Catalyzed C−H Alkenylation with Alkynes
作者:Malay Sen、Nimmakuri Rajesh、Balakumar Emayavaramban、J. Richard Premkumar、Basker Sundararaju
DOI:10.1002/chem.201705183
日期:2018.1.9
A general and efficient procedure for C−H alkenylation of arenes with a broad substrate scope catalyzed by Cp*CoIII was demonstrated with alkynes. A highly selective mono‐alkenylation and sequential bis‐C−H bond functionalization was displayed to exemplify the versatility of the cobalt catalyst. Isolation of cationic Cp*CoIII–alkenyl intermediate was achieved under identical catalytic conditions to
用炔烃证明了由Cp * Co III催化的具有广泛底物范围的芳烃的CH链烯基化的通用有效方法。高选择性的单烯基化和顺序的双CH键功能化显示了钴催化剂的多功能性。在相同的催化条件下实现了阳离子Cp * Co III-烯基中间体的分离,以进一步建立拟议的途径。
Solvent-Free Ruthenium(II)-Catalyzed C-H Activation: Synthesis of Alkenylarylpyrazole Derivatives
作者:Sanchari Shome、Surya Prakash Singh
DOI:10.1002/ejoc.201500634
日期:2015.9
N-arylpyrazoles by using styrenes and acrylates in the presence of Cu(OAc)2·H2O in open air. The highly step-economical C–H bond functionalization process is characterized by a wide substrate scope and significant chemoselectivity, which allowed direct alkenylation to be performed either under solvent-free reaction conditions or by using a user-friendly solvent system in which water was present as the major component
Ruthenium diacetate-catalysed oxidative alkenylation of C–H bonds in air: synthesis of alkenyl N-arylpyrazoles
作者:Percia B. Arockiam、Cedric Fischmeister、Christian Bruneau、Pierre H. Dixneuf
DOI:10.1039/c1gc15875a
日期:——
Ru(OAc)2(p-cymene) catalyses the directed dehydrogenative alkenylation of N-aryl pyrazoles by styrene and alkyl acrylates in the presence of a catalytic or stoichiometric amount of Cu(OAc)2·H2O in air; the acetic acid solvent plays a key role. With arene electron-donating groups, ruthenium-catalysed ortho-dialkenylation with alkyl acrylates can be obtained. A new method to generate the oxidative homocoupling of N-phenylpyrazole is provided with the Ru(OAc)2(p-cymene) catalyst.
The selective 2-mono- and 2,6-divinylations of (N-containing heteroaryl)benzenes can be achieved effectively through rhodium-catalyzed oxidative coupling reactions with alkenes. The installation of two different vinyl groups is also possible by a simple one-pot manner. Thus, a series of 1,3-divinylbenzene derivatives, some of which exhibit solid-state fluorescence, is readily prepared.
Cobalt(III)-Catalyzed Direct <i>ortho</i>
-Alkenylation of Arylpyrazoles: A Comparative Study on Decarboxylation and Desilylation
A comparative study on Co-III-catalyzed direct C-H bond alkenylation of 1-phenylpyrazole derivatives with alkynyl carboxylic acids and arylalkynylsilanes under redox-neutral conditions has been disclosed. These methods show excellent selectivity with good to excellent yields. Trimethylsilylacetylene has been utilized as a vinyl source to obtain the corresponding styrene derivatives. The major differences