Improved contacting of TiO2 catalyst, substrate and light results in an impressive boost in reactor performance for blue light mediated C–H arylation of heteroarenes in continuous-flow mode.

Presented herein is a new complexity-generating method in which both functionalities of α-imino esters undergo stereoselective cyclization with isocyanoacetates to produce directly linked oxazole-imidazolines, which can be transformed into highly functionalized α,β-diamino esters and imidazolinium salts in high diastereo- and enantiopurity.

The synthesis of alkyne- and alkene-decorated lactams has been achieved through a photoredox-initiated radical cascade reaction. The developed Brønsted base assisted, photoredox-catalyzed, intramolecular 5-exo-trig cyclization/intermolecular radical addition/elimination reaction provides facile access to functionalized γ-lactams, with good functional group tolerance and high yields.

Fluorine-containing organic molecules, particularly those that bear (sp3)­C–F bonds, are rapidly gaining prominence in modern chemical synthesis. Although extensive studies have been devoted to the preparation of secondary and tertiary fluorides, crucial shortcomings remain: for example, lengthy substrate synthesis, contrived installation of difficult-to-remove directing/activating units, excessive waste generation and/or limited functional group compatibility. Here, we show that readily accessible α-monofluoro carboxylic acids, which are conventionally difficult substrates for cross-coupling, undergo direct decarboxylative cross-coupling with sp2- and sp3-hybridized organohalides to afford a wide assortment of fluorinated products. Reactions are typically promoted by a combination of 1 mol % of an Ir-based photocatalyst and 2–15 mol % of a bipyridine–Ni complex, delivering products in up to 86% yield under blue LED light irradiation. Concise synthesis of key therapeutic candidates underscores utility, complementarity, and distinct advantages compared with existing methods. DFT calculations are used to rationalize the distinct reactivity of α-fluoro carboxylic acid substrates (vs nonfluorinated parent acids) under decarboxylation conditions.