Visible-light-induced reactions of methylenecyclopropanes (MCPs)

Diverse, visible-light-induced transformations of methylenecyclopropanes (MCPs) have been reported in recent years, attracting significant attention from synthetic chemists. As readily accessible strained molecules, MCPs have sufficient reactivity to selectively generate different target products, through reactions with various radical species upon visible-light irradiation under regulated reaction conditions. These transformations can be classified into three subcategories of reaction pathway, forming ring-opened products, cyclopropane derivatives, and alkynes. These products include pharmaceutical intermediates and polycyclic/heterocyclic compounds that are challenging to obtain using traditional methods. This review summarizes the recent advancements in this field.

Organic synthesis with the most abundant transition metal–iron: from rust to multitasking catalysts

The promising aspects of iron in synthetic chemistry are being explored for three-four decades as a green and eco-friendly alternative to late transition metals. This present review unveils these rich iron-chemistry towards different transformations.

Copper-Catalyzed Bromodifluoroacetylative Cyclization of Enynes

A copper-catalyzed bromodifluoroacetylative cyclization reaction is described. The treatment of bromodifluoroacete derivatives by CuI and B₂Pin₂ enables difluoroalkyl radical generation and triggers the radical addition/cyclization/bromination sequences. Bromodifluoroacetyl-derived ester, amide, and ketone were compatible and gave various vinyl C-Br bonds containing functionalized heterocycles in good yields.

Synthesis of difluoromethylated 2-oxindoles and quinoline-2,4-diones via visible light-induced tandem radical cyclization of N-arylacrylamides

Visible light-induced difluoromethylation of N-arylacrylamides to afford difluoromethylated 2-oxindoles and quinoline-2,4-diones with difluoromethyl 2-pyridyl sulfones as radical precursors has been disclosed.

Mechanistic investigation on radical-induced construction of oxindoles: radical versus electrophilic cyclization

A four-step mechanism is established for the title reaction and the radical cyclization is updated to the cationic cyclization.

A radical coupling reaction of DMSO with sodium arylsulfinates in air : mild utilization of DMSO as C1 resource for the synthesis of arylsulfonyl dibromomethane

A radical coupling reaction of DMSO with ArSO₂Na without the needs of anaerobic atmosphere to afford ArSO₂CHBr₂ is described.

Palladium-catalyzed cascade cyclization of allylamine-tethered alkylidenecyclopropanes: facile access to iodine/difluoromethylene- and perfluoroalkyl-containing 1-benzazepine scaffolds

Palladium-catalyzed radical cascade iododifluoromethylation and iodoperfluoroalkyation/cyclization of allylamine-tethered alkylidenecyclopropanes (ACPs) were developed.

Metal-free cascade cyclization of alkenes toward perfluorinated oxindoles

A simple AIBN-mediated cyclization reaction of activated alkenes toward perfluorinated oxindoles is developed.

Fe-promoted radical cyanomethylation/arylation of arylacrylamides to access oxindoles via cleavage of the sp3 C–H of acetonitrile and the sp2 C–H of the phenyl group

Radical cyanomethylation/arylation of arylacrylamides to access oxindoles with acetonitrile as a radical precursor is described, involving dual C–H bond functionalization.

Metal-free radical cascade dichloromethylation of activated alkenes using CH2Cl2: highly selective activation of the C–H bond

A dicumyl peroxide-initiated highly selective activation of the (sp³)C–H bond in dichloromethane (DCM, CH₂Cl₂) has been achieved, which allows efficient access to dichloronated oxindoles via a free-radical cascade process.