4‐Nitroanisole Facilitates Proton Reduction: Visible Light‐Induced Oxidative Aryltrifluoromethylation of Alkenes with Hydrogen Evolution

Electrochemically-Driven 1,4-Aryl Migration via Radical Fluoromethylation of N-Allylbenzamides: a Straightforward Access to Functionalized β-Arylethylamines

An electrochemical radical Truce Smiles rearrangement of N-allylbenzamides is documented herein. The selective 1,4-aryl migration was triggered by the radical fluoromethylation of the alkene providing a direct route to fluoro derivatives of the highly privileged β-arylethylamine pharmacophore. This practical transformation utilizes readily available starting materials and employs an electrical current to drive the oxidative process under mild reaction conditions. It accommodates a variety of migratory aryl groups with different electronic properties and substitution patterns. Careful selection of the protecting group on the nitrogen atom of the N-allylbenzamide is crucial to outcompete the undesired 6-endo cyclization and achieve high level of selectivity towards the 1,4-aryl migration. DFT calculations support the reaction mechanism and unveil the origin of selectivity between the two competitive pathways.

Photoredox-Catalyzed Alkene Amination: C(sp2)-H/N-H Radical-Radical Cross Dehydrogenative Coupling

Direct alkene C-H/N-H cross dehydrogenative coupling is an infrequent, highly challenging transformation. Herein, a photoredox radical-radical cross-coupling reaction between ketene dithioacetal as a persistent alkene radical cation and azole nitrogen center radical (NCR) was developed. This direct alkene amination proceeded through a synergistic photoredox and cobalt catalysis, with only H2 evolution. The reaction showed excellent tolerance and highly regio- and stereospecific manner, expanding the scope of C(sp2)-N construction methods and radical cross-coupling modes.

Electrochemical or Photoelectrochemical Alkenylpolyfluoroalkylation of 3-Aza-1,5-dienes: Regioselective Entry to Polyfluoroalkylated 4-Pyrrolin-2-ones

An electrochemical or photoelectrochemical regioselective polyfluoroalkylation/cyclization cascade of 3-aza-1,5-dienes with sodium fluoroalkanesulfinates is presented. This protocol proceeds with a broad substrate scope and good functional group tolerance under mild, oxidant-free, transition-metal-free, and electrolyte-free conditions to provide 3-polyfluoroalkylated 4-pyrrolin-2-ones in one step from readily available N-vinylacrylamides, and it is readily scalable to the Gram scale.

Photoinduced Tandem Cyanomethylation/Cyclization of Unsaturated Compounds: Access to Cyanomethylated 7- or 5-Membered N-Heterocycles

A cyanomethylation/cyclization of aryl acetylenes/ethylenes with bromoacetonitrile was finished in a photopromoted condition, which offers an efficient and mild protocol for the preparation of cyanomethylated 7- or 5-membered N-heterocycles with good yields. Meanwhile, trichloroacetonitrile was also compatible with this radical pathway. In addition, a variety of single-crystal X-ray diffraction measurements, scaled-up operations to 1 mmol, functional group transformations of final products, light on/off experiments, and even radial inhibition studies were smoothly performed in this tandem system.

Recent advances in the application of Langlois' reagent in olefin difunctionalization

In this review, we summarise the recent applications of Langlois' reagent in the radical-mediated difunctionalization of alkenes. Among the various trifluoromethylation reagents, Langlois' reagent is an exceptional compound, and many important organic transformations have been realized by employing such reagents. Various organic transformations of Langlois' reagent, especially in radical chemistry, have been developed in recent years. This review describes several key activation methods for Langlois' reagent in the difunctionalization of alkenes by showcasing selected cornerstone research areas and related mechanisms to stimulate the interest of readers in promoting the wider development and application of Langlois' reagent.

Synthesis of Difluoroarymethyl-Substituted Benzimidazo[2,1-a]isoquinolin-6(5H)-ones under Mild Conditions

A highly efficient method for synthesis of difluoroarymethyl-substituted benzimidazo[2,1-a]isoquinolin-6(5H)-ones using 2-arylbenzoimidazoles with α,α-difluorophenylacetic acid as reaction substrates has been developed through radical cascade cyclization. The advantage of this strategy lies in excellent functional group tolerance to generate the corresponding products in good yields under base- and metal-free conditions.

Recent progress in aryltrifluoromethylation reactions of carbon-carbon multiple bonds

Due to the increasing relevance of fluorine-containing organic molecules in drug design, the synthesis of organofluorine compounds has gained high significance in synthetic organic chemistry. Trifluoromethylative difunctionalizations of carbon-carbon multiple bonds, with the simultaneous incorporation of a CF 3 group and another functional element, have considerable potential. Because of the high importance of carbon-carbon bond-forming reactions in organic synthesis, carbotrifluoromethylations and, in particular, aryltrifluoromethylations or heteroaryltrifluoromethylations are considered to be increasing fields of synthetic organic chemistry. The aim of the current review is to summarize recent developments of aryltrifluoromethylation or heteroaryltrifluoromethylation reactions.

Electroreductive synthesis of polyfunctionalized pyridin-2-ones from acetoacetanilides and carbon disulfide with oxygen evolution

A chemical reductant or a sacrificial electron donor is required in any reduction reactions, generally resulting in undesired chemical waste. Herein, we report a reductant-free reductive [3 + 2 + 1] annulation of β-keto amides with CS₂ enabled by the synergy of electro/copper/base using water as an innocuous anodic sacrifice with O₂ as a sustainable by-product. This electrochemical protocol is mild and provides access to polyfunctionalized pyridin-2-ones from simple starting materials in a single step.

Exploring the regioselectivity of the cyanoalkylation of 3-aza-1,5-dienes: photoinduced synthesis of 3-cyanoalkyl-4-pyrrolin-2-ones

Regioselective cyanoalkylalkenylation of 3-aza-1,5-dienes with oxime esters induced by visible light.

The construction of benzimidazo[2,1-a]isoquinolin-6(5H)-ones from N-methacryloyl-2-phenylbenzoimidazoles through radical strategies

Benzimidazo[2,1-a]isoquinolin-6(5H)-one constitutes a structurally unique class of tetracyclic N-heterocycles that are found throughout a myriad of biologically active natural products, pharmaceutical compounds, and functional materials. Various synthetic routes for the preparation of benzimidazo[2,1-a]isoquinolin-6(5H)-ones have been reported. In particular, the use of N-methacryloyl-2-phenylbenzoimidazoles to construct benzimidazo[2,1-a]isoquinolin-6(5H)-ones through various radical strategies have attracted widespread attention due to the versatility and simple preparation of raw materials, as well as the step-economy and mild reaction conditions. Using representative examples, we highlight significant progress in the synthesis of benzimidazo[2,1-a]isoquinolin-6(5H)-ones, including the selection of the catalytic system, substrate scope, mechanistic understanding, and applications. The contents of this review focus on the development of C-, S-, P-, and Si-centered radical addition-intramolecular cyclization strategies.