Iminyl Radical-Triggered 1,5-Hydrogen-Atom Transfer/Heck-Type Coupling by Visible-Light Photoredox Catalysis.

An efficient iminyl radical-triggered 1,5-hydrogen-atom transfer/Heck-type coupling cascade has been achieved through visible-light photoredox catalysis. A variety of unactivated C(sp3)-H bonds have been alkenylated efficiently and selectively with easily available alkenes, providing an elegant route to γ-alkenylated ketone.

Transition-metal free thiocyanooxygenation of functionalized alkenes: facile routes to SCN-containing dihydrofurans and lactones.

An efficient transition-metal free tandem cyclization of functionalized alkenes with easily available thiocyanate salts has been developed under mild conditions. This protocol offers a simple, easy-to-handle, and atom-economical method for the synthesis of SCN-containing dihydrofurans and lactones with good to excellent yields. A detailed mechanistic investigation indicates that a tandem radical pathway is involved in this transformation.

Iminyl Radical-Triggered Intermolecular Distal C(sp3)-H Heteroarylation via 1,5-Hydrogen-Atom Transfer (HAT) Cascade.

An efficient iron-catalyzed intermolecular remote C(sp3)-H heteroarylation of alkyl ketones has been developed via an iminyl radical-triggered 1,5-hydrogen-atom transfer (HAT) cascade. This protocol was amenable to a wide variety of alkyl ketones and heteroaryls, thus providing a straightforward method for the late-stage functionalization of alkylketones and heteroaryls.

Direct C-H Cyanoalkylation of Quinoxalin-2(1H)-ones via Radical C-C Bond Cleavage.

An efficient synthesis of cyanoalkylated heteroarenes via iron-catalyzed direct C-H cyanoalkylation of heteroarenes has been developed. Structurally diverse cyanoalkyl motifs generated through C-C bond cleavage of cyclobutanone oxime esters have been introduced into quinoxalin-2(1H)-ones, flavone, benzothiazoles, and caffeine in good to excellent yields. Remarkably, less-strained cyclopentanone and unstrained cyclohexanone oxime esters were also amenable substrates in this cyanoalkylation reaction.

Iron-Catalyzed Decarboxylative Olefination of Cycloketone Oxime Esters with α,ß-Unsaturated Carboxylic Acids via C-C Bond Cleavage.

An iron-catalyzed redox-neutral, decarboxylative olefination of cycloketone oxime esters with α,ß-unsaturated carboxylic acids has been developed. This reaction involves an iminyl radical mediated C-C bond cleavage/radical addition/decarboxylation cascade. This protocol is highlighted by its low-cost catalytic system and readily accessible starting materials, as well as broad substrate scope, thus providing facile access to structurally diverse cyano-containing alkenes.

Direct C-H Cyanoalkylation of Heteroaromatic N-Oxides and Quinones via C-C Bond Cleavage of Cyclobutanone Oximes.

A direct C-H cyanoalkylation of heteroaromatic N-oxides and quinones with cyclobutanone oximes is reported. This redox-neutral, operationally simple cyanoalkylation reaction is successfully amenable to a wide range of heteroaromatic N-oxides, quinones, and cyclobutanone oximes. A novel catalytic system consisting of a nickel source proved crucial for cleavage of the C-C bond of cyclobutanone oximes and for selective C-C bond formation over ß-hydride elimination. Mechanistic studies suggest that a radical intermediate might be involved in this transformation.