Nickel-Catalyzed Ligand-Controlled Selective Reductive Cyclization/Cross-Couplings

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(5), P. 515 - 535

Published: Jan. 23, 2023

ConspectusThe use of quaternary stereocenters during lead candidate optimization continues to grow because improved physiochemical and pharmacokinetic profiles compounds with higher sp3 fraction. Pd-catalyzed redox-neutral alkene difunctionalization involving carbopalladation alkenes followed by nucleophilic-trapping σ-alkyl-palladium intermediates has been developed as an efficient method construct stereocenters. However, the low chemoselectivity air sensitivity organometallic nucleophiles, well their availability accessibility, limit scope application this elegant strategy. Recently, Ni-catalyzed reductive cross-coupling evolved into a privileged strategy easily valuable C(sp3)-C bonds. Despite great progress, enantioselective coupling C(sp3) electrophiles still relies on activated or functionalized alkyl precursors, which are often unstable require multiple steps prepare. Therefore, via selective cyclization/cross-coupling was developed. This not only offers robust practical alternative for traditional but also provides strategic complementarity electrophiles. In Account, we summarize latest results from our laboratory topic. These findings mainly include explorations in modulating enantioselectivity cyclization mode cyclization/cross-couplings.We will first discuss chiral heterocycles focus effects ligands, reductants, additives roles cross-coupling. A wide range have explored, including aryl halides, vinyl alkynyl gem-difluoroalkenes, CO2, trifluoromethyl alkenes, cyano The synthetic potential approach demonstrated synthesis biologically active natural products drug molecules. Second, detail how tune steric nickel catalysts modifying bipyridine ligands regiodivergent cyclization/cross-couplings. Specifically, bidentate favors exo-selective cyclization/cross-coupling, while carboxylic acid-modified ligand permits endo-selective cyclization/cross-coupling. We show activate amide substrate altering electronic properties substituents nitrogen, thereby enabling nucleophilic addition halides carbonyls. Further investigation led tunable cyclization/cross-couplings (addition carbonyl vs 7-endo-cyclization) divergent pharmacologically important 2-benzazepine frameworks. Finally, serendipitously discover that changing oxidation state can control migratory aptitude different groups, thus providing switchable skeletal rearrangement transformation is high value it represents conceptually unprecedented new C-C bond activation. Thus, Account summarizes methods allow formation using variety insight relationship between structure, substrate, selectivity.

Language: Английский

---

Iron-catalyzed fluoroalkylative alkylsulfonylation of alkenes via radical-anion relay

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Feb. 17, 2024

Abstract Transition metal-catalyzed reductive difunctionalization of alkenes with alkyl halides is a powerful method for upgrading commodity chemicals into densely functionalized molecules. However, super stoichiometric amounts metal reductant and the requirement installing directing group to suppress inherent β-H elimination bring great limitations this type reaction. We demonstrate herein that two different accessible via radical-anion relay Na 2 S O 4 as both sulfone-source. The together electron-shuttle catalyst crucial divert mechanistic pathway toward formation sulfone anion instead previously reported alkylmetal intermediates. Mechanistic studies allow identification carbon-centered radical sulfur-centered radical, which are in equilibrium capture or extrusion SO could be converted accelerated by iron catalysis, leading observed high chemoselectivity.

Language: Английский

---

Photoinduced Regiodivergent and Enantioselective Cross-Coupling of Glycine Derivatives with Hydrocarbon Feedstocks

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

Regiodivergent asymmetric synthesis represents a transformative strategy for the efficient generation of structurally diverse chiral products from single set starting materials, significantly enriching their enantiomeric composition. However, design radical-mediated regiodivergent and enantioselective reactions that can accommodate wide range functional groups substrates has posed significant challenges. The obstacles primarily lie in switching regioselectivity achieving high enantiodiscrimination, especially when dealing with high-energy intermediates. To address these issues, we have developed new catalytic system integrates photoinduced hydrogen atom transfer (HAT) copper catalysis, involving fine-tuning ligands, additives, other reaction parameters. facilitates cross-couplings between N-aryl glycine ester/amide derivatives abundant hydrocarbon feedstocks through strong C(sp3)–H bond activation. This approach allows controlled stereoselective formation C(sp3)–C(sp3) C(sp3)–N bonds, yielding rich variety C- or N-alkylated esters amides commendable yields (up to 92% yield), exclusive regioselectivities (typically >20:1 rr), enantioselectivities 96% ee). Our methodology not only provides promising avenue incorporation alkyl functionalities onto specific sites biologically molecules but also offers practical while simultaneously induction within photochemical reactions.

Language: Английский

---

Nickel‐Catalyzed Switchable Site‐Selective Alkene Hydroalkylation by Temperature Regulation**

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(31)

Published: May 25, 2022

Regiodivergent alkene functionalization that produces either regioisomer starting from the same raw materials is desirable. Herein, we report a nickel-catalyzed switchable site-selective hydroalkylation. The selection of reaction temperatures leads to protocols provide regiodivergent hydroalkylated products single substrate. This protocol allows convenient synthesis α- and β-branched protected amines, both which are important fields pharmaceutical chemistry biochemistry. In addition, enantioenriched alkylamines can be accessed in catalytic asymmetric variant. Preliminary mechanistic studies indicate formation more stable nickelacycle provides driving force migration. thermodynamic kinetic properties different reduction elimination intermediates responsible for site-selectivity.

Language: Английский

---

Switchable 1,2-Rearrangement Enables Expedient Synthesis of Structurally Diverse Fluorine-Containing Scaffolds

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(26), P. 11626 - 11637

Published: May 23, 2022

Skeletal rearrangement that changes the connectivity of molecule via cleavage and reorganization carbon–carbon bonds is a fundamental powerful strategy in complex molecular assembly. Because lack effective methods to control migratory tendency different groups, achieving switchable selectivity skeletal has been long-standing quest. Metal-based dyotropic provides unique opportunity address this challenge. However, remains unexplored. Herein, we show such problem could be solved by modifying ligands on metal catalyst changing oxidation states aptitude thereby providing ligand-controlled, strategy. Experimental density functional theory calculation studies prove rational design. The occurs only when nickel(II) intermediate reduced more nucleophilic nickel(I) species, sterically hindered iPrPDI ligand facilitates 1,2-aryl/Ni rearrangement, while terpyridine promotes 1,2-acyl/Ni rearrangement. This method allows site-selective activation C–C applied for divergent synthesis four medicinally relevant fluorine-containing scaffolds from same starting material.

Language: Английский

---

Pd/NHC-Controlled Regiodivergent Defluorinative Allylation of gem-Difluorocyclopropanes with Allylboronates

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(11), P. 6495 - 6505

Published: May 17, 2022

Controlling the selectivity of synthetically useful reactions has been a longstanding objective organic chemistry. We report regiodivergent synthetic protocol allowing access to diverse fluorinated 1,5-dienes through Pd/NHC-catalyzed ring-opening allylation gem-difluorocyclopropanes. Density functional theory (DFT) calculations on regioselectivity-determining transition states provided critical insight into design NHC ligand for switching regioselectivity. Consistent with DFT predictions, N-heterocyclic carbene (NHC) ligands bulky ortho substituents favored branched allylation, IHept providing > 20:1 branched/linear less hindered such as IMes thermodynamically more stable linear products. were able carry out late-stage modification various complex molecules using this protocol. Our ligand-controlled approach provides efficient regioisomeric from same starting materials and constitutes valuable addition toolbox diversity-oriented synthesis.

Language: Английский

---

Modular Synthesis of Multifunctionalized CF₃-Allenes through Selective Activation of Saturated Hydrocarbons

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(16), P. 10207 - 10221

Published: Aug. 5, 2022

Catalytic 1,4-dicarbofunctionalization of 1,3-enynes is a powerful strategy for the synthesis polysubstituted allenes. Despite impressive progress, such still restricted to use alkyl-metallic reagents or pre-activated radical precursors, thus limiting its functional group compatibility and atom economy. Herein, we report that through combination decatungstate photo-hydrogen transfer nickel catalysis, three-component 2-trifluoromethyl-1,3-enynes achieved. This allows modular tetrasubstituted CF3-allenes under exceptionally mild conditions. A variety electrophiles as aryl bromides, alkenyl acyl chlorides, alkynyl bromides were successfully employed traps lead desired products. Another significant advantage most abundant hydrocarbons are used feedstocks, wide range synthetically versatile groups complex drug-like structures can be easily incorporated. Based on experimental density theories, possible catalytic cycle involving 1,3-nickel rearrangement proposed.

Language: Английский

---

Enantioselective Nickel-Catalyzed Reductive Aryl/Alkenyl–Cyano Cyclization Coupling to All-Carbon Quaternary Stereocenters

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(11), P. 4776 - 4782

Published: March 9, 2022

An enantioselective nickel-catalyzed intramolecular reductive cross-coupling of C(sp2) electrophiles and cyano groups is reported. Enantioenriched CN-containing all-carbon quaternary stereocenters are assembled by desymmetrizing cyclization aryl/alkenyl halide-tethered malononitriles. The use an organic reductant, (EtO)2MeSiH, crucial to the enantioselectivity reactivity. Applications method demonstrated through synthesis bioactive molecules their cyanated analogues total natural product diomuscinone. This study exhibits potential coupling strategies access structurally rigid synthetically versatile from readily available starting materials.

Language: Английский

---

Nickel‐Catalyzed Defluorinative Asymmetric Cyclization of Fluoroalkyl‐Substituted 1,6‐Enynes for the Synthesis of Seletracetam

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(46)

Published: Sept. 23, 2022

Abstract The introduction of fluorine‐containing groups into organic molecules can significantly affect their physical and chemical properties has long been used as an effective strategy for drug discovery development. Consequently, the development catalytic asymmetric methods synthesis heterocycles is highly desirable sought after. Herein, we describe a nickel‐catalyzed defluorinative cyclization fluoroalkyl‐substituted 1,6‐enynes, providing expedient access to synthetically attractive 4‐fluorovinyl‐substituted 2‐pyrrolidones in good yields with remarkable high levels chemo‐, regio‐, enantioselectivities (90–99 % ee,>35 examples). This protocol features readily available starting materials excellent functional group compatibility, exhibits complementary regioselectivity. utility this was demonstrated enantioselective antiepileptic Seletracetam.

Language: Английский

---

Enantioselective nickel-catalyzed dicarbofunctionalization of 3,3,3-trifluoropropene

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Sept. 21, 2022

Despite paramount applications of chiral trifluoromethylated compounds in medicinal chemistry and materials science, limited strategies have been developed for catalytic asymmetric synthesis such valuable fluorinated structures. Here, we report a nickel catalyzed enantioselective dicarbofunctionalization inexpensive industrial chemical 3,3,3-trifluoropropene (TFP) with readily available tertiary alkyl aryl iodides. The reaction overcomes the β-F elimination side TFP, proceeds efficiently under mild conditions. protocol possesses advantages, as synthetic convenience, high enantioselectivity, excellent functional group tolerance, providing rapid straightforward access to interest.

Language: Английский

---