Cobalt‐Catalyzed Direct Arylation of Unactivated Arenes with Aryl Halides
作者:Wei Liu、Hao Cao、Jie Xin、Liqun Jin、Aiwen Lei
DOI:10.1002/chem.201002290
日期:2011.3.21
and simple: The directarylation of unactivatedarenes with aryl halides has been carried out with [Co(acac)3] as the catalyst and LiHMDS as the base. The corresponding biaryl compounds have been prepared in good to excellent yields and at a relatively low reaction temperature (see scheme; acac=acetylacetonate, LiHMDS=lithium bis(trimethylsilyl)amide). An intramolecular directarylation has also been
Tandem CH activation/arylation between unactivated arenes and aryl halides catalyzed by iron complexes that bear redox‐active non‐innocent bisiminopyridine ligands is reported. Similar reactions catalyzed by first‐row transition metals have been shown to involve substrate‐based aryl radicals, whereas our catalytic system likely involves ligand‐centered radicals. Preliminary mechanistic investigations
Constructing biaryls through direct aromatic CH functionalization of unactivatedarenes has become a popular topic in organic chemistry. Many efficient methods have been developed. In this Communication, a directarylation of unactivatedarenes with a broad range of aryl iodides is reported. This reaction proceeds through a new type of amine‐catalyzed single electron transfer initiated radical coupling
Organocatalysis in Cross-Coupling: DMEDA-Catalyzed Direct C−H Arylation of Unactivated Benzene
作者:Wei Liu、Hao Cao、Hua Zhang、Heng Zhang、Kin Ho Chung、Chuan He、Haibo Wang、Fuk Yee Kwong、Aiwen Lei
DOI:10.1021/ja103050x
日期:2010.12.1
by using DMEDA as the catalyst to promote the direct C-H arylation of unactivated benzene in the presence of potassium tert-butoxide. The arylation of unactivated benzene with aryliodides, or arylbromides and even chlorides under the assistance of an iodo-group, could simply take place at 80 °C. The new methodology presumably involves an arylradical anion as an intermediate. This finding offers
Several amino acids were tested to catalyze the transition-metal-free direct C–H arylation of unactivated benzene derivatives. Among them, proline was found to be an excellent catalyst for the cross-coupling between aryl halides and unactivatedarenes. The reaction presumably involves an aryl radical anion as the intermediate based on several experiments. The reaction using this catalyst system offers