Dicarbofunctionalizations of an Unactivated Alkene via Photoredox/Nickel Dual Catalysis

1,2-Acylphosphinylation of Styrenes to Access β-Aryl-γ-ketophosphine Oxides by Irradiation-Induced Radical Relay

An acylphosphinylation reaction has been devised for the synthesis of β-aryl-γ-ketophosphine oxides, employing styrenes and acyl azolium salts through an irradiation-induced radical relay mechanism. This method effectively constructs C-C and C-P bonds while demonstrating excellent functional group tolerance. Mechanistic studies revealed that a radical-addition-coupling-elimination cascade process was involved in this reaction.

Ni-Catalyzed Regioselective Alkylarylation of Unactivated Alkenes in Amines Enabled by Cooperative Ligand Effects of Nitriles and Electron-Deficient Alkenes

We report a Ni-catalyzed vicinal alkylarylation of unactivated alkenes in γ,δ- and δ,ε-alkenylamines with aryl halides and alkylzinc reagents. The reaction is enabled by amine coordination and can use all primary, secondary, and tertiary amines. The reaction constructs two new C(sp3)-C(sp3) and C(sp3)-C(sp2) bonds and produces δ- and ε-arylamines with C(sp3)-branching at the γ- and δ-positions. A variety of aryl and heteroaryl iodides and both the primary and secondary alkylzinc reagents can be used as coupling carbon sources. Mechanistic studies suggest that the reaction is enabled by the cooperative effect of organic nitriles and electron-deficient alkenes (EDAs) as ligands.

Iron-Mediated Dialkylation of Alkenylarenes with Benzyl Bromides

We disclose a method for the dibenzylation of alkenylarenes with benzyl bromides using iron powder. This reaction generates branched alkyl scaffolds adorned with functionalized aryl rings through the formation of two new C(sp3)-C(sp3) bonds at the vicinal carbons of alkenes. This protocol tolerates electron-rich, electron-neutral, and electron-poor benzyl bromides and alkenylarenes. Mechanistic studies suggest the formation of benzylic radical intermediates as a result of single-electron transfer from the iron, which is intercepted by alkenylarenes.

Visible-light-induced photocatalytic four-component fluoroalkylation-dithiocarbamylation via difunctionalization of styrenes

Herein we demonstrate that a visible-light-induced photocatalytic four-component fluoroalkylation-dithiocarbamylation is a unified method for the fluoroalkylation of diverse activated fluoroalkyl halides, including monofluoroalkyl bromides, difluoroalkyl bromides, trifluoromethyl iodide, and perfluoroalkyl iodides. The synthetic value of this method has been demonstrated by the transformations of various substrates containing drug/natural product skeletons, gram scale reactions, and further derivatizations of the fluorodithiocarbamate products. This work features an atom economical protocol that is simple to operate, does not require any additives or strong bases, and can be carried out under mild conditions.

Recent advances in dual photoredox/nickel catalyzed alkene carbofunctionalised reactions

Alkene carbofunctionalization reactions have great potential for synthesizing complex molecules and constructing complex structures in natural products and medicinal chemistry. Recently, dual photoredox/nickel catalysis has emerged as a novel strategy for alkene carbofunctionalization. Nickel offers numerous advantages over other transition metals, such as cost-effectiveness, abundance, and low toxicity, and moreover, it has many oxidation states. Nickel catalysts exhibit excellent catalytic activity in dual photoredox/transition metal catalysis, facilitating the formation of carbon-carbon or carbon-heteroatom bonds in organic transformations. This review highlights the latest advancements in dual photoredox/nickel-catalyzed alkene carbofunctionalizations and includes the literature published from 2020 to 2024.

Ni-Catalyzed Linearizable Cyclization/Coupling with Detachable Silicon-Oxygen Linker: Access to 1,2-Oxasilolanes, 3-Hydroxysilanes and 4-Arylalkanols

We disclose a Ni-catalyzed cyclization/alkylmetal interception reaction in which products are readily linearized to permit regiodefined alkene dicarbofunctionalization. This method offers a convenient route to access 1,2-oxasilolane heterocycles, 3-hydroxysilanes and 4-arylalkanols with the formation of C(sp3)-C(sp3) bonds at primary and secondary alkyl carbon centers. In this reaction, a silicon-oxygen (Si-O) bond functions as a detachable linker that can be delinked with several hydride, alkyl, aryl and vinyl nucleophiles to create profusely functionalized 3-hydroxysilanes. A silicon motif in the cyclic C(sp3)-Si-O construct in 1,2-oxasilolane heterocycles can also be selectively deleted by Pd-catalyzed hydrodesilylation affording Si-ablated linear alcohol products reminiscent of vicinal ethylene dicarbofunctionalization with C(sp3) and C(sp2) carbon sources.

A free-radical design featuring an intramolecular migration for a synthetically versatile alkyl-(hetero)arylation of simple olefins

A free-radical approach has enabled the development of a synthetically versatile alkyl-(hetero)arylation of olefins. Alkyl and (hetero)aryl groups were added concurrently to a full suite of mono- to tetrasubstituted simple alkenes (i.e., without requiring directing or electronically activating groups) for the first time. Key advances also included the introduction of synthetically diversifiable alkyl groups featuring different degrees of substitution, good diastereocontrol in both cyclic and acyclic settings, the addition of biologically valuable heteroarenes featuring Lewis basic nitrogen atoms as well as simple benzenes, and the generation of either tertiary or quaternary benzylic centers. The synthetic potential of this transformation was demonstrated by leveraging it as the key step in a concise synthesis of oliceridine, a new painkiller that received FDA approval in 2020.

Nickel-Catalyzed Regioselective Intermolecular Dialkylation of Alkenylarenes: Generation of Two Vicinal C(sp3 )-C(sp3 ) Bonds Across Alkenes

We disclose a Ni-catalyzed regioselective dialkylation reaction of alkenylarenes with α-halocarbonyls and alkylzinc reagents. The reaction produces γ-arylated alkanecarbonyl compounds with the generation of two new C(sp3 )-C(sp3 ) bonds at the vicinal carbons of alkenes. This reaction is effective for the use of primary, secondary and tertiary α-halocarboxylic esters, amides and ketones in conjunction with primary and secondary alkylzinc reagents as the sources of two C(sp3 ) carbons for the dialkylation of terminal and cyclic internal alkenes.

Directed Nickel-Catalyzed Selective Arylhydroxylation of Unactivated Alkenes under Air

An expeditious and novel nickel-catalyzed selective arylhydroxylation of unactivated alkenes with arylboronic acids was developed. This protocol is compatible with β,γ- and γ,δ-alkene amides, including traditionally challenging internal alkenes, to provide important β-arylethylalcohol scaffolds. The free hydroxyl group in the final product could be smoothly further transformed into other functional groups. Control experiments indicated that the oxygen atom of the hydroxyl group in the product is derived from the oxygen in the air.