Synthesis of N-Acylcarbazoles through Palladium-Catalyzed Aryne Annulation of 2-Haloacetanilides

Regioselective ortho halogenation of N-aryl amides and ureas via oxidative halodeboronation: harnessing boron reactivity for efficient C-halogen bond installation

The installation of the C-halogen bond at the ortho position of N-aryl amides and ureas represents a tool to prepare motifs that are ubiquitous in biologically active compounds. To construct such prevalent bonds, most methods require the use of precious metals and a multistep process. Here we report a novel protocol for the long-standing challenge of regioselective ortho halogenation of N-aryl amides and ureas using an oxidative halodeboronation. By harnessing the reactivity of boron over nitrogen, we merge carbonyl-directed borylation with consecutive halodeboronation, enabling the precise introduction of the C-X bond at the desired ortho position of N-aryl amides and ureas. This method offers an efficient, practical, and scalable solution for synthesizing halogenated N-heteroarenes under mild conditions, highlighting the superiority of boron reactivity in directing the regioselectivity of the reaction.

Palladium(0)-catalyzed aryne annulation: a powerful strategy for the synthesis of thio-bridged compounds

A method for the construction of various thio-bridged compounds is developed using readily available o-(trimethylsilyl)aryl triflates as a source of aryne precursor, catalyzed by simple Pd(dba)₂/dppe complex. This operationally simple and modular protocol allows thio-bridged compound via C(sp²)-C(sp²) and C(sp²)-C(sp³) bond formation in promising yields with a broad substrate scope. The key part is in situ generation of an aryne from o-(trimethylsilyl)aryl triflates and their subsequent intermolecular annulation.

Aryne Annulations for the Synthesis of Carbocycles and Heterocycles: An Updated Review

Carbocycles and heterocycles are the most relevant structural moieties, which find boundless applications in interdisciplinary areas. In this regard, the interesting chemistry of aryne is highly embraced by the researchers for the synthesis of structurally different polycyclic systems i.e. carbocycles and heterocycles. In this review, we intended to provide a comprehensive overview on annulative approach considering Kobayashi's aryne intermediate as the key reactive species with diverse nucleo-/electrophilic partners. The review highlights the different aryne annulation reactions adopted for the synthesis of carbocycles and heterocycles (covering articles mainly from middle of 20’s), showcasing their viability towards broad range of substrates bearing diverse functionalities.

Applications of Palladium-Catalyzed C-N Cross-Coupling Reactions

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.