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。
Mild Rhodium(III)-Catalyzed Direct CH Allylation of Arenes with Allyl Carbonates
作者:Honggen Wang、Nils Schröder、Frank Glorius
DOI:10.1002/anie.201301165
日期:2013.5.10
All(yl) possible! A rhodium(III)‐catalyzed intermolecular directCHallylation reaction utilizing readily accessible allylcarbonates was developed. This method allows the allylation of electron‐neutral arenes, providing complete γ‐selectivity, high isomeric ratio, good substrate scope, and excellent functional group compatibility.
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.
Acceleration of Amide Bond Rotation by Encapsulation in the Hydrophobic Interior of a Water-Soluble Supramolecular Assembly
作者:Michael D. Pluth、Robert G. Bergman、Kenneth N. Raymond
DOI:10.1021/jo800991g
日期:2008.9.19
exploits the hydrophobic effect for the encapsulation of tertiary amides. Variable-temperature (1)H NMR experiments reveal that the free energy barrier for rotation around the C-N amide bond is lowered by up to 3.6 kcal/mol upon encapsulation. The hydrophobic cavity of the assembly is able to stabilize the less polar transition state of the amiderotation process. Carbon-13 labeling studies showed that the
Versatile directed aromatic C–H bond activation and oxidative coupling with allylicalcohols is reported using a cationic Rh(III) catalyst. This method provides efficient and robust synthesis of functional β-aryl ketones and indolines in good yields with excellent regioselectivity, even the reaction runs at 3 g scale. The catalytic systems have good functional group tolerance, such as CONR2, NHAc,