Remote aromatic metalation. An anionic Friedel-Crafts equivalent for the regioselective synthesis of condensed fluorenones from biaryl and m-teraryl 2-amides
摘要:
Remote metalation (t-BuLi, LDA) of m-teraryl and biaryl amides (Scheme I) constitutes a short and convenient route to a variety of substituted and condensed fluorenones, including aza analogues (Table I) and the natural product, dengibsinin (6a, Scheme II).
Rhodium(III) and Hexabromobenzene-A Catalyst System for the Cross-Dehydrogenative Coupling of Simple Arenes and Heterocycles with Arenes Bearing Directing Groups
can be used as the cooxidant/catalyst modifier for the [RhIIICp*]‐catalyzed (Cp*=C5Me5) dehydrogenativecross‐coupling of benzamides with simple benzene derivatives (see scheme, DG=directing group). Similarly, heterocycles can be coupled and druglike structures formed. Mechanistic studies suggest a unique and multiple role of the Cu(OAc)2/C6Br6 system and a nonchelate‐assisted CH activation as the
C 6 Br六和 毒品!C 6 Br 6可用作苯甲酰胺与简单苯衍生物的[Rh III Cp *]催化(Cp * = C 5 Me 5)脱氢交叉偶联的助氧化剂/催化剂改性剂(请参见方案,DG =指导基团)。类似地,杂环可以偶联并形成药物样结构。机理研究表明,Cu(OAc)2 / C 6 Br 6系统具有独特的多重作用,而非螯合物辅助的CH活化是决定速率的步骤。
ortho-Substituted unsymmetrical biaryls from aryl tert-butyl sulfones
作者:Jonathan Clayden、Marc Julia
DOI:10.1039/c39930001682
日期:——
Nickel-catalysed coupling of arylmagnesium halides with aryl tert-butyl sulfones, and in particular with those bearing ortrto-substituents introduced by ortholithiation, gives ortho-substituted unsymmetrical biaryls.
[RhIIICp*]-Catalyzed Dehydrogenative ArylAryl Bond Formation
作者:Joanna Wencel-Delord、Corinna Nimphius、Frederic W. Patureau、Frank Glorius
DOI:10.1002/anie.201107842
日期:2012.2.27
Directed, undirected! Rhodium(III)‐catalyzed double CH bond activation (one directed, one undirected) provides an efficient route to biaryls (see scheme; DG=directing group). Significant kinetic isotope effects for both reaction partners and H/D scrambling between them are interesting experimental findings. While the mechanism is still unclear, a rhodium(V) species is invoked in the catalytic cycle
A mild and efficient protocol for the high para-selective arylation of monosubstituted arenes with tertiary benzamides has been developed via palladium-catalyzedoxidative coupling reactions. Due to the mild conditions and the easy availability of substrates and oxidant, this method could potentially provide a practical approach for the synthesis of para-substituted biaryl compounds.