Metal-Free Direct C3-H Alkylation and Arylation of Quinoxalin-2(1H)-Ones with Inert Alkyl and Aryl Chlorides

In the present manuscript, we reported the first visible-light-enabled direct C3-H alkylation/arylation of quinoxalin-2(1H)-ones with unactivated alkyl/aryl chlorides under metal-free conditions. A wide range of unactivated alkyl and aryl chlorides containing different functionalities are coupled with a variety of quinoxalin-2(1H)-one derivatives under mild reaction conditions to afford the C3-alkyl/aryl substituted quinoxalin-2(1H)-ones in moderate to good yields.

Photoinduced Decarboxylative C3-H Alkylation of Quinoxalin-2(1H)-ones

An efficient, catalyst- and additive-free, visible-light-driven radical C3-H alkylation of quinoxalin-2(1H)-one derivatives has been developed. This reaction utilizes alkyl-NHP-esters as an alkyl radical donor and quinoxalin-2(1H)-one derivatives as an alkyl radical acceptor. The operationally simple protocol works under mild reaction conditions and tolerates a variety of functional groups. Furthermore, the synthetic utility of the methodology was successfully implemented for synthesizing biologically relevant C3-alkyl substituted quinoxalin-2(1H)-one derivatives.

Photoinduced ligand to metal charge transfer enabling cerium mediated decarboxylative alkylation of quinoxalin-2(1H)-ones

Here, we report the cerium-mediated decarboxylative alkylation of quinoxalin-2(1H)-ones utilizing feedstock carboxylic acids as a radical precursor via photoinduced-LMCT. This operationally simple protocol overcomes the limitation of the direct use of carboxylic acids to access alkyl radicals. Spectroscopic investigations reveal the photoinduced LMCT and CO₂ evolving events. We have utilized a broad range of alkyl carboxylic acids (1° to 3° acids), amino acids and pharmaceutically-important acids as a coupling partner to synthesise the desired alkylated heterocyclic product in good to excellent yields.

Catalytic Enantioselective Isocyanide-Based Reactions: Beyond Passerini and Ugi Multicomponent Reactions

The development of catalytic enantioselective isocyanide-based reactions is currently of great interest because the resulting products are valuable in organic synthesis, pharmacological chemistry, and materials science. This review assembles and comprehensively summarizes the recent achievements in this rapidly growing area according to the reaction types. Special attention is paid to the advantages, limitations, possible mechanisms, and synthetic applications of each reaction. In addition, a personal outlook on the opportunities for further exploration is given at the end.

Decarboxylative C–H alkylation of heteroarenes by copper catalysis

A copper-catalyzed decarboxylative C–H alkylation of heteroarenes with alkyl carboxylic acids has been realized.

Diastereoselective Synthesis of 1,3-Diyne-Tethered Trifluoromethylcyclopropanes through a Sulfur Ylide Mediated Cyclopropanation/DBU-Mediated Epimerization Sequence

A one-pot synthesis of 1,3-diyne-tethered trifluoromethylcyclopropanes starting from 2-CF₃-3,5-diyne-1-enes and sulfur ylides via a sulfur ylide mediated cyclopropanation and a DBU-mediated epimerization sequence is described in this work. This process is highly diastereoselective with broad substrate scope. Moreover, a series of synthetic transformations based on the diyne moieties were conducted smoothly, affording cyclopropanes featuring trifluoromethyl-substituted all-carbon quaternary centers.