Fluoro and fauna: The incorporation of CF₂H groups into organic compounds has attracted much recent attention, owing to the broad applications of CF₂H-containing compounds in pharmaceuticals and agrochemicals. Metal-catalyzed direct difluoromethylation represents one of the most powerful tools for the synthesis of difluoromethylated compounds. This Focus Review describes the recent developments and remaining challenges in this field.

Delightful deficiency: Because of its vacant p orbital, an incorporated boron atom can imprint peculiar optoelectronic properties on polycyclic aromatic hydrocarbons (PAHs). Recently, synthetic strategies have been developed to provide access to B-PAHs that are specifically tailored to applications as catalysts for the activation of small molecules or as luminophores and charge carriers in optoelectronic devices.

Good morning sunshine! Visible-light photoredox decarboxylative coupling reactions have become an important chemical transformation because of their wide substrate scope, mild reaction conditions, high efficiency, and practicability. Herein, we have summarized recent advances in this synthetic strategy, which include details regarding the formation of C−C and C−Y (Y=heteroatom) bonds.

All at C: In this Focus Review, phosphine-mediated catalytic methods for the enantioselective construction of all-carbon quaternary stereogenic centers are highlighted and discussed.

Soak up the sun! This review describes recent advances in the synthesis of organophosphorus compounds by employing methods such as photoredox catalysis, transition-metal complex/photoredox dual catalytic systems that incorporate phosphine ligands, and photoredox catalysis in the presence of organophosphorus compounds as organocatalysts.

(0) what a night: This Focus Review describes Pd-catalyzed alkene carboheterofunctionalization reactions between aryl/alkenyl/alkynyl halides or triflates and alkenes that contain pendant nucleophiles for the construction of heterocycles.

Oxygenation reactions promoted by visible light: The development of visible-light-mediated oxygenation reactions utilizing molecular oxygen has been briefly summarized based on the type of newly formed chemical bond. Synthetic organic methodologies and mechanistic studies have been discussed.

An elemental match! Carbon–nitrogen bonds are ubiquitous in organic chemistry. This review presents some recent advances in redox reactions that use elemental sulfur and molecular iodine as excellent reagents/catalysts to provide these important linkages.

Direct route: A Cu-catalyzed DABSO-based aerobic oxidative reaction of hydrazines and amines has been developed. The hydrazines were explored as new aryl precursors for the coupling reaction, without the use of any additional additives, affording the sulfonamides with good chemical yields. This new method proceeds with the release of nitrogen, providing an easy and practical strategy for the preparation of sulfonamides.

S−F 49ers: Methods for the synthesis of fluorosulfates from the reactions of phenols and alcohols with sulfuryl fluoride, fluorosulfonic acid, sulfuryl chloride fluoride, and fluorosulfonic anhydride are summarized. The broad application of fluorosulfates in synthetic transformations, which include catalyzed amination, cross-coupling, sulfur(VI) fluoride exchange, carbonylation, hydrolysis, and alcoholysis, are also discussed.

Only a little bit of iodine: A synthetic strategy for an iodine-mediated sulfonylation of quinoline N-oxides has been developed. A wide variety of 2-sulfonyl quinoline derivatives were synthesized by reacting various quinoline N-oxides with different sodium sulfinates in the presence of sub-stoichiometric amounts of I₂ in one pot, after 2 h at room temperature.

Activator-free: An additive-free photoredox-catalyzed trifluoromethylthiolation of aromatic alkenes has been developed. Trifluoromethanesulfenyl radical (^.SCF₃) is efficiently generated from a photocatalyst and an electrophilic triflouromethylthiolating reagent. This photoredox system induces a regioselective oxytrifluoromethylthiolation of carbon–carbon double bonds through catalytic processes without any activator.

Antioxidant organoselenium compounds: A simple and rapid method for the selective synthesis of 3-(organylselanyl)-1 H-indoles and 3-(organylselanyl)imidazo[1,2-a]pyridines catalyzed by CuI/SeO₂ under ultrasound irradiation was developed. This protocol employs a diverse range of 1 H-indoles or imidazo[1,2-a]pyridines and diorganyl diselenides to afford the corresponding products selectively in good to excellent yields, the antioxidant activity of which was evaluated by using a wide range of in vitro assays.

C−H and Co: Both low-valent and high-valent cobalt catalysts have been applied to the functionalization reactions of a variety of aliphatic C−H bonds over the past decade. In this Focus Review, cobalt-catalyzed C(sp³)−H functionalization reactions are summarized according to the type of catalyst and mode of C−H activation.

HyperIodine! Photoredox-mediated Minisci alkylation of electron-deficient N-heteroarenes with aliphatic carboxylic acids has been developed. The iodonium ester intermediate, in situ formed from carboxylic acid and acetoxybenziodoxole oxidant, is the alkylation reagent. Excellent substrate scope and good functional group tolerance were demonstrated under mild reaction conditions.

The synthesis of natural products remains at the forefront of organic reactions. C−H bond activation plays a crucial role towards these syntheses. This review focuses on the recent advances in natural product synthesis that have been carried out by transition-metal-mediated C−H activation. Applications to natural products and the synthetic utility of this methodology are also outlined in this Focus Review.

The road to addition: The advent of the thia-Michael addition reaction in organic synthesis and its ever-burgeoning applications in the fields of medicinal chemistry, catalysis, drug discovery, and materials science has been a profound scientific development. This Focus Review plots the journey of the thia-Michael addition reaction in organic synthesis, and is categorized according to catalyzed and catalyst-free thia-Michael addition reaction.

How to functionalize C5: This review is focused on the remote C5-H functionalization of 8-aminoquinolinamide derivatives, which includes not only C−C bond formation reactions but also carbon–heteroatom bond formations such as C−X (X=F, Cl, Br, I) C−S, C−Se, C−N, C−O, C−P. This review covers all the literature reports on C5-H functionalization of the 8-aminoquinoline moiety to date. In most cases, the C5 position is activated through single electron transfer by employing either metal catalysts, photocatalysts, or metal-free conditions.

Selective modifications: Chromones and coumarins contain a chemically distinct C−H bonds that can be converted into valuable functional groups for the purpose of constructing compounds with diverse pharmacological profiles. This review presents recent advances in the efficient modification of chromones and coumarins by employing site-selective C−H bond functionalizations.

In the cross-fire: This Focus Review highlights recent advances in the Liebeskind–Srogl cross-coupling reaction of a wide variety of organosulfur compounds with different organometallic reagents, and its applications in organic synthesis.