Transition Metal-Catalyzed C–H Amination: Scope, Mechanism, and Applications

Chemical Reviews, Journal Year: 2017, Volume and Issue: 117(13), P. 9247 - 9301

Published: Jan. 4, 2017

Catalytic transformation of ubiquitous C-H bonds into valuable C-N offers an efficient synthetic approach to construct N-functionalized molecules. Over the last few decades, transition metal catalysis has been repeatedly proven be a powerful tool for direct conversion cheap hydrocarbons synthetically versatile amino-containing compounds. This Review comprehensively highlights recent advances in intra- and intermolecular amination reactions utilizing late metal-based catalysts. Initial discovery, mechanistic study, additional applications were categorized on basis scaffolds types reactions. Reactivity selectivity novel systems are discussed three sections, with each being defined by proposed working mode.

Language: Английский

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Selective formation of γ-lactams via C–H amidation enabled by tailored iridium catalysts

Science, Journal Year: 2018, Volume and Issue: 359(6379), P. 1016 - 1021

Published: March 1, 2018

Intramolecular insertion of metal nitrenes into carbon-hydrogen bonds to form γ-lactam rings has traditionally been hindered by competing isocyanate formation. We report the application theory and mechanism studies optimize a class pentamethylcyclopentadienyl iridium(III) catalysts for suppression this pathway. Modulation stereoelectronic properties auxiliary bidentate ligands be more electron-donating was suggested density functional calculations lower C-H barrier favoring desired reaction. These transform wide range 1,4,2-dioxazol-5-ones, carbonylnitrene precursors easily accessible from carboxylic acids, corresponding γ-lactams via sp3 sp2 amidation with exceptional selectivity. The power method further demonstrated successful late-stage functionalization amino acid derivatives other bioactive molecules.

Language: Английский

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Catalytic Transformations of Functionalized Cyclic Organic Carbonates

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(42), P. 13735 - 13747

Published: June 6, 2018

Functionalized cyclic organic carbonates and related heterocycles have emerged as highly versatile heterocyclic substrates for ring-opening decarboxylative catalytic transformations allowing the development of new stereo- enantioselective C-N, C-O, C-C, C-S C-B bond formation reactions. Transition-metal-mediated conversions only recently been rejuvenated powerful approaches towards preparation more complex molecules. This minireview will highlight potential structurally with a focus on their synthetic value mechanistic manifolds that are involved upon conversion.

Language: Английский

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Experimental and Theoretical Studies on Rhodium-Catalyzed Coupling of Benzamides with 2,2-Difluorovinyl Tosylate: Diverse Synthesis of Fluorinated Heterocycles

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(9), P. 3537 - 3545

Published: Feb. 8, 2017

Fluorinated heterocycles play an important role in pharmaceutical and agrochemical industries. Herein, we report on the synthesis of four types fluorinated via rhodium(III)-catalyzed C—H activation arenes/alkenes versatile coupling with 2,2-difluorovinyl tosylate. With N-OMe benzamide being a directing group (DG), reaction delivered monofluorinated alkene retention tosylate functionality. Subsequent one-pot acid treatment allowed efficient 4-fluoroisoquinolin-1(2H)-ones 5-fluoropyridin-2(1H)-ones. When N—OPiv benzamides were used, however, [4 + 2] cyclization occurred to provide gem-difluorinated dihydroisoquinolin-1(2H)-ones. Synthetic applications have been demonstrated ready availability both arene partner highlighted synthetic potentials these protocols. Mechanistically, two processes share common process involving N—H deprotonation, activation, olefin insertion form 7-membered rhodacycle. Thereafter, different pathways featuring β-F elimination C—N bond formation are followed basis density functional theory (DFT) studies. These DG-dependent led open chain products, respectively. The mechanistic rationale was supported by detailed DFT In particular, origins intriguing selectivity competing versus elucidated. It found that is facile event proceeds syn-coplanar transition state low energy barrier. migratory Rh—C(alkyl) into Rh(V) amido species. reactions, turnover-limiting, which stays good agreement experimental

Language: Английский

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Design and Optimization of Catalysts Based on Mechanistic Insights Derived from Quantum Chemical Reaction Modeling

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(11), P. 6509 - 6560

Published: May 8, 2019

Until recently, computational tools were mainly used to explain chemical reactions after experimental results obtained. With the rapid development of software and hardware technologies make modeling more reliable, they can now provide valuable insights even become predictive. In this review, we highlighted several studies involving predictions unexpected reactivities or providing mechanistic for organic organometallic that led improved results. Key these successful applications is an integration between theory experiment allows incorporation empirical knowledge with precise computed values. Computer already a standard tool being embraced by ever increasing group researchers, it clear its utility in predictive reaction design will increase further near future.

Language: Английский

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Asymmetric formation of γ-lactams via C–H amidation enabled by chiral hydrogen-bond-donor catalysts

Nature Catalysis, Journal Year: 2019, Volume and Issue: 2(3), P. 219 - 227

Published: Feb. 18, 2019

Language: Английский

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Dioxazolones: Stable Substrates for the Catalytic Transfer of Acyl Nitrenes

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(8), P. 4751 - 4769

Published: March 30, 2020

Dioxazolones are a convenient class of acyl nitrene transfer reagents. Their application in homogeneous transition-metal catalysis has led to many new amidation reactions. typically activated by transition metals at relatively low reaction temperatures. The metal nitrenoids formed decarboxylative activation dioxazolones generally electron deficient and commonly react concerted fashion. "Intermolecular" insertion reactions involving preactivated C–H bonds ("inner-sphere" mechanism) easily compete with the Curtius-type rearrangement, but for intramolecular "direct" transfer/insertion nonpreactivated substrates (i.e., without preceding formation metal–carbon or metal–hydride bonds) extensive ligand optimization is important prevent such unwanted side ease dioxazolone synthesis, CO2 gas as sole byproduct from dioxazolones, importance general development several interesting producing N-aryl amides, oxazoles, lactams. Since proceeds under mild conditions, stereo- enantioselective also possible, which useful synthesis bioactive nitrogen-containing compounds. This review provides an overview these reported recent years.

Language: Английский

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Ir-Catalyzed Intermolecular Branch-Selective Allylic C–H Amidation of Unactivated Terminal Olefins

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(6), P. 2268 - 2273

Published: Feb. 4, 2019

An efficient method for intermolecular branch-selective allylic C–H amidation has been accomplished via Ir(III) catalysis. The reaction proceeds through initial activation, supported by the isolation and crystallographic characterization of an allyl-Ir(III) intermediate, followed a subsequent oxidative with readily available dioxazolones as nitrenoid precursors. A diverse range amides are successfully installed at branched position terminal alkenes in good yields regioselectivities. Importantly, allows use amide-derived precursors avoiding problematic Curtius-type rearrangements.

Language: Английский

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Mechanism-Guided Development of Transition-Metal-Catalyzed C–N Bond-Forming Reactions Using Dioxazolones as the Versatile Amidating Source

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(11), P. 2683 - 2700

Published: May 12, 2021

ConspectusCatalytic reactions that construct carbon–nitrogen bonds are one of central themes in both synthetic and medicinal chemistry since the obtainable nitrogen-containing motifs commonly encountered natural products have also seen a growing prominence as key structural features marketed drugs preclinical candidates. Pd-catalyzed cross-couplings, such Buchwald–Hartwig amination, at forefront methods practical settings. However, they require prefunctionalized substrates (hetero)aryl halides must be prepared independently, often by multiple operations. One emerging way to circumvent these preparatory steps directly convert ubiquitous C–H into valuable C–N is catalytic which allows chemists devise shorter more efficient retrosynthetic schemes. The past two decades witnessed considerable progress expanding repertoire this strategy, especially identifying effective amino group precursors. In context, dioxazolones experienced dramatic resurgence recent years versatile nitrogen source combination with transition-metal catalyst systems facilitate decarboxylation access metal-acylnitrenoid intermediates. addition their high robustness easy accessibility from abundant carboxylic acids, unique reactivity transient intermediates amido transfer has led fruitful journey for mild amidation reactions.This Account summarizes our contributions development bond-forming using nitrenoid precursors, categorized subsets according mechanistic differences: inner- versus outer-sphere pathways. first section describes how we could unveil potential realm inner-sphere amidation, where demonstrated serve not only manageable alternatives acyl azides but highly reagents significantly reduce loading temperature. Taking advantage conditions 9 Cp*M complexes (M = Rh, Ir, Co) or isoelectronic Ru species, dramatically expanded accessible scope. Mechanistic investigations revealed putative metal-nitrenoid species involved intermediate during catalysis, leads facile bond formation. On basis underpinning, succeeded developing novel platforms harness intermediacy metal-nitrenoids explore insertion via an pathway. Indeed, tailored catalysts were capable suppressing competitive Curtius-type decomposition, thus granting lactam products. We further repurposed upon modification chelating ligands identity transition metal achieve three goals: (i) addressing selectivity issues control regio-, chemo-, enantioselectivities, (ii) sustainable catalysis first-low metals, (iii) navigating chemical space (di)functionalization alkenes/alkynes. Together own research efforts, highlighted herein some important relevant advances other groups. finally conclude brief overview eye toward developments.

Language: Английский

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Iridium-Catalyzed Enantioselective C(sp³)–H Amidation Controlled by Attractive Noncovalent Interactions

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(17), P. 7194 - 7201

Published: April 12, 2019

While remarkable progress has been made over the past decade, new design strategies for chiral catalysts in enantioselective C(sp3)–H functionalization reactions are still highly desirable. In particular, ability to use attractive noncovalent interactions rate acceleration and enantiocontrol would significantly expand current arsenal asymmetric metal catalysis. Herein, we report development of a Ir(III)-catalyzed intramolecular amidation reaction dioxazolone substrates synthesis optically enriched γ-lactams using newly designed α-amino-acid-based ligand. This Ir-catalyzed proceeds with excellent efficiency outstanding enantioselectivity both activated unactivated alkyl bonds under very mild conditions. It offers first general route γ-alkyl γ-lactams. Water was found be unique cosolvent achieve γ-aryl lactam production. Mechanistic studies revealed that ligands form well-defined groove-type pocket around Ir center. The hydrophobic effect this allows facile stereocontrolled binding polar or aqueous media. Instead capitalizing on steric repulsions as conventional approaches, catalyst operates through an unprecedented mechanism nitrenoid C–H insertion featuring multiple interactions.

Language: Английский

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