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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Chiral Carboxylic Acid Assisted Enantioselective C–H Activation with Achiral Cp^xM^III (M = Co, Rh, Ir) Catalysts

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(11), P. 6455 - 6466

Published: May 17, 2021

Enantioselective C–H functionalization is a powerful tool for synthesizing chiral molecules. In the past few years, combination of high-valent group 9 metals with achiral Cpx ligands and carboxylic acids (CCA) has emerged as promising catalytic system to enable selective cleavage enantiotopic bonds. This Perspective summarizes background, catalyst design, applied reactions in detail, followed by discussion future directions.

Language: Английский

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Weak-Coordination in C–H Bond Functionalizations Catalyzed by 3d Metals

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(6), P. 3452 - 3506

Published: March 3, 2022

Transition-metal-catalyzed C–H bond functionalizations have had an enormous influence on organic synthesis in recent times. However, the use of low-abundance 4d and 5d metals is almost inevitable, they are high demand. This will be a cause concern, hence, it important to develop methods based 3d metals, which widely present Earth's crust. In this regard, metal catalysts or their precursors for catalysis, general, functionalizations, particular, has gained significant momentum The major development catalytic with been achieved predominantly strongly coordinating directing groups such as pyridyl, pyrimidinyl, pyrazolyl, 8-amino-quinolinyl groups. Thus, prefunctionalization substrates these necessary, contradicts step- atom-economy activation. commonly available functional aldehyde, ketone, carboxylic acid, amide, hydroxy, N-oxides loosely bind through weak-coordination. These weakly orient activate regioselectively without need preinstalled Although challenging, contemporary topic actively pursued by many researchers Through article, we provide comprehensive overview metal-catalyzed, coordinating, directing-group-enabled reported until March 2021.

Language: Английский

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Nitrene-mediated intermolecular N–N coupling for efficient synthesis of hydrazides

Nature Chemistry, Journal Year: 2021, Volume and Issue: 13(4), P. 378 - 385

Published: March 22, 2021

Language: Английский

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Cobalt(III)/Chiral Carboxylic Acid‐Catalyzed Enantioselective Synthesis of Benzothiadiazine‐1‐oxides via C−H Activation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(28)

Published: May 2, 2022

Abstract Among sulfoximine derivatives containing a chiral sulfur center, benzothiadiazine‐1‐oxides are important for applications in medicinal chemistry. Here, we report that the combination of an achiral cobalt(III) catalyst and pseudo‐ C 2 ‐symmetric H 8 ‐binaphthyl carboxylic acid enables asymmetric synthesis from sulfoximines dioxazolones via enantioselective C−H bond cleavage. With optimized protocol, with several functional groups can be accessed high enantioselectivity.

Language: Английский

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Mechanistic snapshots of rhodium-catalyzed acylnitrene transfer reactions

Science, Journal Year: 2023, Volume and Issue: 381(6657), P. 525 - 532

Published: July 20, 2023

Rhodium (Rh) acylnitrene complexes are widely implicated in catalytic C-H amidation reactions but have eluded isolation and structural characterization. To overcome this challenge, we designed a chromophoric octahedral Rh complex with bidentate dioxazolone ligand, which photoinduced metal-to-ligand charge transfer initiates amidation. X-ray photocrystallographic analysis of the Rh-dioxazolone allowed elucidation targeted Rh-acylnitrenoid provided firm evidence that singlet nitrenoid species is primarily responsible for acylamino reactions. We also monitored crystallo reaction nucleophile situ-generated Rh-acylnitrenoid, crystallographically traceable system to capture mechanistic snapshots transfer.

Language: Английский

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Interweaving Visible‐Light and Iron Catalysis for Nitrene Formation and Transformation with Dioxazolones

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(30), P. 16426 - 16435

Published: April 12, 2021

Abstract Herein, visible‐light‐driven iron‐catalyzed nitrene transfer reactions with dioxazolones for intermolecular C(sp 3 )‐N, N=S, and N=P bond formation are described. These occur exogenous‐ligand‐free process feature satisfactory to excellent yields (up 99 %), an ample substrate scope (109 examples) under mild reaction conditions. In contrast intramolecular C−H amidations strategies, regioselective amidation via visible‐light‐induced is devised. Mechanistic studies indicate that the proceeds a radical pathway. Computational show decarboxylation of dioxazolone depends on conversion ground sextet state dioxazolone‐bounding iron species quartet spin visible‐light irradiation.

Language: Английский

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Highly Robust Iron Catalyst System for Intramolecular C(sp³)−H Amidation Leading to γ‐Lactams

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(6), P. 2909 - 2914

Published: Oct. 28, 2020

Abstract Disclosed here is the use of an iron catalyst system for intramolecular C−H amidation toward γ‐lactam synthesis from dioxazolone precursors. (Phthalocyanine)Fe III Cl was found to catalyze this cyclization with extremely high turnover numbers up 47 000 under mild and aerobic conditions. On basis experimental computational mechanistic studies, reaction suggested proceed by a stepwise radical pathway involving fast hydrogen atom abstraction followed rebound. A plausible origin along air‐compatibility also rationalized.

Language: Английский

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Merging NiH Catalysis and Inner-Sphere Metal-Nitrenoid Transfer for Hydroamidation of Alkynes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(15), P. 5867 - 5877

Published: April 9, 2021

The formal hydroamination/hydroamidation utilizing metal hydride is an appealing synthetic tool for the construction of valuable nitrogen-containing compounds from unsaturated hydrocarbons. While significant advances have been made functionalizations alkenes in this realm, direct hydroamidation alkynes remains rather limited due to high feasibility key metal-alkenyl intermediate choose other reaction pathways. Herein, we report a NiH-catalyzed strategy with dioxazolones, which allows convenient access synthetically useful secondary enamides (E)-anti-Markovnikov or Markovnikov selectivity. viable both terminal and internal also tolerant range subtle functional groups. With H2O found as essential component catalyst turnovers, involvement inner-sphere nitrenoid transfer proposed that outcompetes undesired semireduction process, thus representing first example show competence Ni catalysis metal-nitrenoid formation dioxazolones.

Language: Английский

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Unravelling nitrene chemistry from acyclic precursors: recent advances and challenges

Organic Chemistry Frontiers, Journal Year: 2021, Volume and Issue: 8(7), P. 1677 - 1693

Published: Jan. 1, 2021

Recent advances in nitrene chemistry from acyclic precursors are reviewed this paper.

Language: Английский

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