Oxidative Annulation of Diphenylpropanamides via In Situ Hypervalent Iodine-Promoted Intramolecular C–N/C–O Bond Formation

An aryl iodide catalyzed intramolecular oxidative transformation of diphenylpropanamide derivatives is described that can readily afford the C–N/C–O coupling products in a single step. The speed of the 1,3-aryl iodide migration process determines the diversity of target compound generation in this reaction. This straightforward approach can be performed with the use of inexpensive and readily available catalyst, transition-metal-free, mild conditions and good functional group tolerance.

The aryl iodine-catalyzed organic transformation via hypervalent iodine species generated in situ

The application of hypervalent iodine species generated in situ in organic transformations has emerged as a useful and powerful tool in organic synthesis, allowing for the construction of a series of bond formats via oxidative coupling. Among these transformations, the catalytic aryl iodide can be oxidized to hypervalent iodine species, which then undergoes oxidative reaction with the substrates and the aryl iodine regenerated again once the first cyclic cycle of the reaction is completed. This review aims to systematically summarize and discuss the main progress in the application of in situ-generated hypervalent iodine species, providing references and highlights for synthetic chemists who might be interested in this field of hypervalent iodine chemistry.

Aryl radical-mediated N-heterocyclic carbene catalysis

There have been significant advancements in radical reactions using organocatalysts in modern organic synthesis. Recently, NHC-catalyzed radical reactions initiated by single electron transfer processes have been actively studied. However, the reported examples have been limited to catalysis mediated by alkyl radicals. In this article, the NHC organocatalysis mediated by aryl radicals has been achieved. The enolate form of the Breslow intermediate derived from an aldehyde and thiazolium-type NHC in the presence of a base undergoes single electron transfer to an aryl iodide, providing an aryl radical. The catalytically generated aryl radical could be exploited as an arylating reagent for radical relay-type arylacylation of styrenes and as a hydrogen atom abstraction reagent for α-amino C(sp3)–H acylation of secondary amides.

Copper Immobilization on Fe3o4@Agar: An Efficient Superparamagnetic Nanocatalyst for Green Buchwald-Hartwig Cross-coupling Reaction of Primary and Secondary Amines With Aryl Iodide Derivatives

Immobility of copper on magnetic nanoparticles was performed using surface rectification of Fe3O4 with Agar. The magnetic Fe3O4@Agar-Cu nanocatalyst was prepared and entirely characterized by different analyses such as Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), energy dispersive X-ray (EDX), thermogravimetric (TGA), and inductively coupled plasma (ICP). The nanocatalyst was applied in C-N bond formation through the cross-coupling reaction of aryl halides with primary or secondary amines in water as a green medium known as the Buchwald-Hartwig reaction. The results of the Buchwald-Hartwig reaction by Fe3O4@Agar-Cu magnetic nanoparticles as catalyst demonstrate excellent activity and stability in water. Moreover, this catalyst can be recycled several times without considerable loss in its activity.