Directed Nickel-Catalyzed Diastereoselective Reductive Difunctionalization of Alkenyl Amines

Fe3+-mediated selective 1,2-Se (S) bifunctionalization of olefin

A one-pot, four-component reaction for simultaneously constructing C-Se, C-S, and C-N bonds via iron-mediated olefin 1,2-bifunctionalization was described. β-Selenylethyl dithiocarbamates were obtained highly efficiently with a wide substrate scope and remarkable regioselectivity. Notably, non-activated olefins exhibit higher reactivity in this reaction system, achieving yields of up to 99%.

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.

Cross-Electrophile Coupling: Principles, Methods, and Applications in Synthesis

Cross-electrophile coupling (XEC), defined by us as the cross-coupling of two different σ-electrophiles that is driven by catalyst reduction, has seen rapid progression in recent years. As such, this review aims to summarize the field from its beginnings up until mid-2023 and to provide comprehensive coverage on synthetic methods and current state of mechanistic understanding. Chapters are split by type of bond formed, which include C(sp3)-C(sp3), C(sp2)-C(sp2), C(sp2)-C(sp3), and C(sp2)-C(sp) bond formation. Additional chapters include alkene difunctionalization, alkyne difunctionalization, and formation of carbon-heteroatom bonds. Each chapter is generally organized with an initial summary of mechanisms followed by detailed figures and notes on methodological developments and ending with application notes in synthesis. While XEC is becoming an increasingly utilized approach in synthesis, its early stage of development means that optimal catalysts, ligands, additives, and reductants are still in flux. This review has collected data on these and various other aspects of the reactions to capture the state of the field. Finally, the data collected on the papers in this review is offered as Supporting Information for readers.

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.

Nickel-Catalyzed 8-Aminoquinoline Directed Reductive Dialkylcyclization/Homodialkylation of Unactivated Alkenes

Chemo and regioselective dialkylation of alkene is an efficient protocol for constructing useful chemicals, but challenges remain in the unrestricted application of alkylating reagents. Alkyl bromide belongs to the easy-to-access and operable alkyl electrophiles that can be used in reductive coupling with alkenes. Here, we reported convenient strategies for dialkylcyclization and homodialkylation of unactivated β,γ- and γ,δ-unsaturated alkenyl amides with 1,3-dibromoalkanes or primary alkyl bromides under nickel-catalyzed reductive conditions that exhibited high regioselectivity and functional-group tolerance.

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.

Directed Asymmetric Nickel-Catalyzed Reductive 1,2-Diarylation of Electronically Unactivated Alkenes

Transition-metal catalyzed intermolecular 1,2-diarylation of electronically unactivated alkenes has emerged as an extensive research topic in organic synthesis. However, most examples are mainly limited to terminal alkenes. Furthermore, transition-metal catalyzed asymmetric 1,2-diarylation of unactivated alkenes still remains unsolved and is a formidable challenge. Herein, we describe a highly efficient directed nickel-catalyzed reductive 1,2-diarylation of unactivated internal alkenes with high diastereoselectivities. More importantly, our further effort towards enantioselective 1,2-diarylation of the unactivated terminal and challenging internal alkenes is achieved, furnishing various polyarylalkanes featuring benzylic stereocenters in high yields and with good to high enantioselectivities and high diastereoselectivities. Interestingly, the generation of cationic Ni-catalyst by adding alkali metal fluoride is the key to increased efficiency of this enantioselective reaction.

Ni-Catalyzed Regioselective Reductive 1,3-Dialkenylation of Alkenes

Dicarbofunctionalization is an important efficient synthetic technique for adding two chemical moieties across an alkene. Here, a novel method of reductive dicarbofunctionalization has been developed using a single alkenyl triflate as the electrophile, combined with an unactivated alkene. The reaction does not require an external auxiliary and proceeds with complete regioselectivity.

Nickel-Catalyzed 1,2-Arylboration of Unactivated Alkenes to Access Boryl-Functionalized Aliphatic Amines

We report herein a three-component 1,2-arylboration of alkenyl amines bearing a cleavable picolinamide directing group. With aryl halides as electrophiles and B₂Pin₂ as nucleophiles, a wide range of alkenes could be converted into valuable boryl-functionalized aliphatic amines. The reaction proceeds with high levels of chemo- and regiocontrol and exhibits high functional group tolerance. In addition, the pinacol boronic ester group could undergo various transformations, indicating that the protocol could potentially provide a platform for versatile regioselective difunctionalization of alkenyl amines.

Directed Copper-Catalyzed Tandem Radical Cyclization Reaction of Alkyl Bromides and Unactivated Olefins

The free radical cyclization reaction is a promising strategy for ring framework formation. Herein, we report a copper-catalyzed tandem radical cyclization strategy for preparing substituted lactam derivatives. This reaction proceeds through a radical coupling approach, which not only allows a wide range of alkenes but also is quite compatible with the primary, secondary, and tertiary radicals. In addition, density functional theory calculations were performed to gain insights into the reaction mechanism.

Remote arylalkylation of unactivated alkenes via 6- or 7-membered nickelacycles with excellent diastereofidelity

We developed a nickel-catalyzed remote arylalkylation of unactivated alkenes via kinetically and thermodynamically disfavored 6- and 7-membered nickelacycles.

The cobalt(ii)-catalyzed acyloxylation of picolinamides with bifunctional silver carboxylate via C–H bond activation

The cobalt(ii)-catalyzed C–H bond acyloxylation of picolinamides with bifunctional silver carboxylate has been developed. The mild and practical esterification provides an atom-economic route to access to polysubstituted naphthalene compounds.

Regioselective 1,2-carbosulfenylation of unactivated alkenes via directed nickel catalysis

A removable bidentate picolinamide assisted regioselective 1,2-carbosulfenylation of unactivated alkenes with aryl/alkenylboronic acids and disulfide electrophiles has been developed with a cost-effective and air-stable Ni(ii) precatalyst.