Electrocatalytic Formal C(sp2)-H Alkylations via Nickel-Catalyzed Cross-Electrophile Coupling with Versatile Arylsulfonium Salts.

Producing sp3-hybridized carbon-enriched molecules is of particular interest due to their high success rate in clinical trials. The installation of aliphatic chains onto aromatic scaffolds was accomplished by nickel-catalyzed C(sp2)-C(sp3) cross-electrophile coupling with arylsulfonium salts. Thus, simple non-prefunctionalized arenes could be alkylated through the formation of aryldibenzothiophenium salts. The reaction employs an electrochemical approach to avoid potentially hazardous chemical redox agents, and importantly, the one-pot alkylation proved also viable, highlighting the robustness of our approach.

Electrochemical assembly of isoxazoles via a four-component domino reaction.

Multicomponent domino reactions via electrochemical annulations have emerged as a robust strategy for the rapid assembly of heterocyclics. Herein, an electrochemical annulation via a [1 + 2 + 1 + 1] four-component domino reaction was accomplished in a user-friendly undivided cell setup to assemble valuable five-membered isoxazole motifs. Our approach is characterized by a high level functional group tolerance and operational simplicity, avoiding the tedious and time-consuming preparation of pre-functionalized substrates. Detailed mechanistic studies were conducted including isotopic labeling, kinetic studies, cyclic voltammetry (CV) analysis, and intermediate characterization, providing support for a radical pathway.

Bifurcated Rhodaelectro-catalyzed C-H Activation for the Synthesis of Pyrroles and Lactones.

While electrocatalyzed alkyne annulations of arenes represent a powerful strategy for the assembly of heteroaromatic motives, electrochemical C(sp2)-H activations of alkenes remain scarce. Herein, a strategy for the rhodaelectro-catalyzed functionalization of enamides is presented for the efficient construction of pyrroles using electricity as a sustainable oxidant. Moreover, the tuning of the solvent system allowed a fascinating switch in chemoselectivity, which is not possible with traditionally used chemical oxidants, giving rise to lactone architectures. The rhoda-electrocatalysis features a broad scope as well as high regio- and chemoselectivities.

The crucial role of silver(I)-salts as additives in C-H activation reactions: overall analysis of their versatility and applicability.

Transition-metal catalyzed C-H activation reactions have been proven to be useful methodologies for the assembly of synthetically meaningful molecules. This approach bears intrinsic peculiarities that are important to be studied and comprehended in order to achieve its best performance. One example is the use of additives for the in situ generation of catalytically active species. This strategy varies according to the type of additive and the nature of the pre-catalyst that is being used. Thus, silver(I)-salts have proven to play an important role, due to the resulting high reactivity derived from the pre-catalysts of the main transition metals used so far. While being powerful and versatile, the use of silver-based additives can raise concerns, since superstoichiometric amounts of silver(I)-salts are typically required. Therefore, it is crucial to first understand the role of silver(I) salts as additives, in order to wisely overcome this barrier and shift towards silver-free systems.