Transition metal-catalyzed alkene isomerization as an enabling technology in tandem, sequential and domino processes

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 50(2), P. 1391 - 1406

Published: Dec. 10, 2020

One-pot reactions based on catalytic isomerization of alkenes not only offer the inherent advantages atom-, step- and redox-economy but also enable preparation value-added products that would be difficult to access by conventional methods.

Language: Английский

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Light-empowered contra-thermodynamic stereochemical editing

Nature Reviews Chemistry, Journal Year: 2022, Volume and Issue: 7(1), P. 35 - 50

Published: Nov. 16, 2022

Language: Английский

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Enantioselective Nickel‐Catalyzed Migratory Hydrocyanation of Nonconjugated Dienes

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(48), P. 21436 - 21441

Published: Aug. 12, 2020

Abstract Metal‐catalyzed chain‐walking reactions have recently emerged as a powerful strategy to functionalize remote positions in organic molecules. However, protocol for nonconjugated dienes remains scarcely reported, and developments are currently ongoing. In this Communication, nickel‐catalyzed asymmetric hydrocyanation of involving process is demonstrated. The reaction exhibits excellent regio‐ chemoselectivity, wide range substrates were tolerated, delivering the products high yields enantioselectivities. Deuterium‐labeling experiments support process, which involves an iterative β‐H elimination reinsertion processes. Gram‐scale synthesis, regioconvergent experiments, downstream transformations gave further insights into potential transformation.

Language: Английский

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γ-Selective C(sp3)–H amination via controlled migratory hydroamination

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Sept. 27, 2021

Abstract Remote functionalization of alkenes via chain walking has generally been limited to C(sp 3 )–H bonds α and β polar-functional units, while γ -C(sp through controlled alkene transposition is a longstanding challenge. Herein, we describe NiH-catalyzed migratory formal hydroamination alkenyl amides achieved chelation-assisted control, whereby various amino groups are installed at the -position aliphatic chains. By tuning olefin isomerization ligand directing group optimization, -selective amination can be stabilization 6-membered nickellacycle by an 8-aminoquinoline subsequent interception aminating reagent. A range amines bond unactivated with varying alkyl lengths, enabling late-stage access value-added -aminated products. Moreover, employing picolinamide-coupled substrates, this approach further extended δ amination. The chain-walking mechanism pathway selectivity investigated experimental computational methods.

Language: Английский

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Contra-Thermodynamic Positional Isomerization of Olefins

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 144(1), P. 137 - 144

Published: Dec. 30, 2021

A light-driven method for the contra-thermodynamic positional isomerization of olefins is described. In this work, stepwise PCET activation a more substituted and thermodynamically stable olefin substrate mediated by an excited-state oxidant Brønsted base to afford allylic radical that captured Cr(II) cocatalyst furnish allylchromium(III) intermediate. situ protodemetalation allylchromium complex methanol highly regioselective affords isomerized less alkene product. The higher oxidation potential isomer renders it inert further oxidant, enabling accumulate in solution over course reaction. broad range isopropylidene substrates are accommodated, including enol ethers, enamides, styrenes, 1,3-dienes, tetrasubstituted alkyl olefins. Mechanistic investigations step also presented.

Language: Английский

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Catalytic, contra-Thermodynamic Positional Alkene Isomerization

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 144(1), P. 145 - 152

Published: Dec. 30, 2021

The positional isomerization of C═C double bonds is a powerful strategy for the interconversion alkene regioisomers. However, existing methods provide access to thermodynamically more stable isomers from less starting materials. Here, we report discovery dual catalyst system that promotes contra-thermodynamic under photochemical irradiation, providing terminal directly conjugated, internal utility method demonstrated in deconjugation diverse electron-rich/electron-poor alkenes and through strategic application natural product synthesis. Mechanistic studies are consistent with regiospecific bimolecular homolytic substitution (SH2′) mechanism proceeding an allyl-cobaloxime intermediate.

Language: Английский

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Nickel-Catalyzed Regio- and Enantioselective Hydroamination of Unactivated Alkenes Using Carbonyl Directing Groups

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(20), P. 9091 - 9100

Published: May 11, 2022

The asymmetric addition of an N–H bond to various alkenes via a direct catalytic method is powerful way synthesizing value-added chiral amines. Therefore, the enantio- and regioselective hydroamination unactivated remains appealing goal. Here, we report highly Ni-catalyzed readily available bearing weakly coordinating native amides or esters. This succeeds for both terminal internal has broad amine coupling partner scope. mild reaction process well suited late-stage functionalization complex molecules potential gain modular access enantioenriched β- γ-amino acid derivatives 1,2- 1,3-diamines. Mechanistic studies reveal that bisoxazoline-bound Ni specie effectively leverages carbonyl coordination achieve NiH insertion into alkenes.

Language: Английский

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Modulating stereoselectivity in allylic C(sp3)-H bond arylations via nickel and photoredox catalysis

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Feb. 1, 2023

Abstract While significant progress has been made in developing selective C-H bond cross-couplings the field of radical chemistry, site and stereoselectivity remain a long-standing challenge. Here, we present successful development stereodivergent allylic C(sp 3 )-H arylations through systematic investigation direction degree cross-coupling process. In contrast to signature photosensitized geometrical isomerization alkenes, catalytic reaction demonstrates feasibility switching C-C double by means ligand control as well steric electronic effects. Computational studies explain stereochemical outcome indicate that excitation Ni-allyl complex from singlet triplet state results spontaneous change allyl group coordination subsequent can be directed choice achieve E / Z selectivity.

Language: Английский

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Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(4), P. 1323 - 1463

Published: Feb. 14, 2024

This review surveys the synthesis and reactivity of low-oxidation state metalate anions d-block elements, with an emphasis on contributions reported between 2006 2022. Although field has a long rich history, chemistry transition been greatly enhanced in last 15 years by application advanced concepts complex ligand design. In recent years, potential highly reactive complexes fields small molecule activation homogeneous catalysis become increasingly evident. Consequently, exciting applications have developed, including catalytic transformations. article intends to guide reader through fascinating world low-valent metalates. The first part describes metalates stabilized assortment frameworks, carbonyls, isocyanides, alkenes polyarenes, phosphines phosphorus heterocycles, amides, redox-active nitrogen-based ligands. Thereby, will be familiarized impact different types physical chemical properties addition, ion-pairing interactions metal–metal bonding may dramatic influence structures reactivities. ramifications these effects are examined separate section. second is devoted toward inorganic molecules such as H2, N2, CO, CO2, P4 related species. It shown that use electron-rich translates into impressive hydrogenation organic reduction CO2. results discussed this illustrate being tapped for challenging processes relevance energy conversion. Therefore, it hoped serve useful resource inspire further developments dynamic research field.

Language: Английский

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Stereodivergent, Kinetically Controlled Isomerization of Terminal Alkenes via Nickel Catalysis

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(21)

Published: March 18, 2024

Abstract Because internal alkenes are more challenging synthetic targets than terminal alkenes, metal‐catalyzed olefin mono‐transposition (i.e., positional isomerization) approaches have emerged to afford valuable E ‐ or Z‐ from their complementary alkene feedstocks. However, the applicability of these methods has been hampered by lack generality, commercial availability precatalysts, and scalability. Here, we report a nickel‐catalyzed platform for stereodivergent / Z ‐selective synthesis at room temperature. Commercial reagents enable this one‐carbon transposition ‐internal via Ni−H‐mediated insertion/elimination mechanism. Though mechanistic regime is same in both systems, underlying pathways that lead each active catalysts distinct, with catalyst forming comproportionation an oxidative addition complex followed substrate protonation metal trialkylphosphonium salt additive. In case, ligand sterics denticity control stereochemistry prevent over‐isomerization.

Language: Английский

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