We report the visible-light-induced radical coupling reaction of silyl enol ethers with α-bromocarbonyl compounds to give 1,4-dicarbonyls. The reaction was effectively accelerated using an inexpensive organic dye (eosin Y) as a photoredox catalyst. 1,4-Dicarbonyl compounds alone were afforded, without the generation of carbonyl adducts of the α-halocarbonyls, which are usually generated in the presence of fluoride anions or Lewis acids. A variety of silyl enol ethers, α-bromoketones, α-bromoesters, and α-bromoamides were applied to this system to produce the coupling compounds.

Organicd yes are an attractive alternative to the use of transition-metalc omplexes in photoredox catalysis. Herein, we report an inexpensive organic dye (eosin Y)catalyzed radical coupling of a-bromocarbonyl compounds with allyltrifluoroborates under visible light irradiation. This reactionw as accelerated by either Bu 4 NF or CsF.B ased on mechanistic studies, the cation exchange between potassium allyltrifluoroborate and Bu 4 NF proceeded to generate KF.T he generatedK Fo rC sF acts as aL ewis acid to promote as ingle electron transfer (SET) from eosin Yt oa-halocarbonyls. The protocol was applied to bromoesters, bromoketones,a nd bromoamides to give the coupling products in high yields.

Fluorinated compounds have become important in the fields of agrochemical industry, pharmaceutical chemistry and materials sciences. Accordingly, various methods for their preparation have been developed in the past. Fluorinated compounds can be accessed via conjugation with fluorinated building blocks, via CÀ H fluorination or via selective activation of perfluorinated compounds to give the partially fluorinated congeners. Especially the direct activation of CÀ F bonds, one of the strongest σ-bonds, still remains challenging and new strategies for CÀ F activation are desirable. Herein a method for the photochemical activation of aromatic CÀ F bonds is presented. It is shown that isonitriles selectively insert into aromatic CÀ F bonds while aliphatic CÀ F bonds remain unaffected. Mechanistic studies reveal the reaction to proceed via the indirect excitation of the isonitrile to its triplet state by photoexcited acetophenone at 350 nm. Due to the relatively mild light used, the process shows high functional group tolerance and various compounds of the class of benzimidoyl fluorides are accessible from aryl isonitriles and commercially available perfluorinated arenes.

A coupling between various alkynylstannanes with α-iodo esters was catalyzed by GaBr3 under UV irradiation conditions, for which a catalytic amount of GaBr3 was essential, and a radical coupling with the generated alkynylgallium species was involved. The desired α-alkynyl esters were selectively obtained even in the presence of an aryl–I bond, which is a reactive site in a conventional palladium-catalyzed system.

A new highly anti‐diastereoselective Michael addition of α‐alkoxy ketones to α,β‐unsaturated ketones was achieved. This method features a dual‐catalyst protocol that combines samarium(III) trifluoromethanesulfonate and Bu3SnOMe. The combination of these two catalysts effectively allowed the generation of enolate species from α‐alkoxy ketones and produced Michael adducts in high yields with high anti diastereoselectivity. A variety of enones and α‐alkoxy ketones were applied to this system to give the anti products. One‐pot domino Michael/aldol reactions effectively afforded cyclic enones with a defined configuration.