Dioxazolones: Stable Substrates for the Catalytic Transfer of Acyl Nitrenes

ACS Catalysis, Год журнала: 2020, Номер 10(8), С. 4751 - 4769

Опубликована: Март 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.

Язык: Английский

---

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

Accounts of Chemical Research, Год журнала: 2021, Номер 54(11), С. 2683 - 2700

Опубликована: Май 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.

Язык: Английский

---

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

Nature Chemistry, Год журнала: 2021, Номер 13(4), С. 378 - 385

Опубликована: Март 22, 2021

Язык: Английский

---

Mechanistic snapshots of rhodium-catalyzed acylnitrene transfer reactions

Science, Год журнала: 2023, Номер 381(6657), С. 525 - 532

Опубликована: Июль 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.

Язык: Английский

---

An overview on copper in industrial chemistry: From ancient pigment to modern catalysis

Coordination Chemistry Reviews, Год журнала: 2025, Номер 529, С. 216438 - 216438

Опубликована: Янв. 17, 2025

Язык: Английский

---

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

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(30), С. 16426 - 16435

Опубликована: Апрель 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.

Язык: Английский

---

Ligand Redox Noninnocence in [Co^III(TAML)]^0/– Complexes Affects Nitrene Formation

Journal of the American Chemical Society, Год журнала: 2019, Номер 142(1), С. 552 - 563

Опубликована: Дек. 17, 2019

The redox noninnocence of the TAML scaffold in cobalt-TAML (tetra-amido macrocyclic ligand) complexes has been under debate since 2006. In this work, we demonstrate with a variety spectroscopic measurements that backbone anionic complex [CoIII(TAMLred)]– is truly noninnocent and one-electron oxidation affords [CoIII(TAMLsq)]. Multireference (CASSCF) calculations show electronic structure [CoIII(TAMLsq)] best described as an intermediate spin (S = 1) cobalt(III) center antiferromagnetically coupled to ligand-centered radical, affording overall doublet 1/2) ground-state. Reaction cobalt(III)-TAML PhINNs nitrene precursor leads TAML-centered produces radical without metal ion. ligand state (TAMLred or TAMLsq) determines whether mono- bis-nitrene are formed. results formation [CoIII(TAMLq)(N•Ns)] [CoIII(TAMLq)(N•Ns)2]–, respectively. Herein, ligand-to-substrate single-electron transfer one-electron-reduced Fischer-type radicals (N•Ns–) intermediates catalytic styrene. These species were characterized by EPR, XANES, UV–vis spectroscopy, high-resolution mass spectrometry, magnetic moment measurements, supporting CASSCF calculations.

Язык: Английский

---

Synthesis of N-acyl sulfenamides via copper catalysis and their use as S-sulfenylating reagents of thiols

Nature Communications, Год журнала: 2022, Номер 13(1)

Опубликована: Окт. 28, 2022

Abstract Sulfur–heteroatom bonds such as S–S and S–N are found in a variety of natural products often play important roles biological processes. Despite their widespread applications, the synthesis sulfenamides, which feature that may be cleaved under mild conditions, remains underdeveloped. Here, we report method for N -acyl sulfenamides via copper-catalyzed nitrene-mediated S -amidation reaction thiols with dioxazolones. This is efficient, convenient, broadly applicable. Moreover, resulting -acetyl highly effective -sulfenylation reagents unsymmetrical disulfides conditions. The protocol enables facile access to sterically demanding difficult synthesize by other means.

Язык: Английский

---

Investigation on flotation separation of bastnaesite from calcite and barite with a novel surfactant: Octylamino-bis-(butanohydroxamic acid)

Separation and Purification Technology, Год журнала: 2020, Номер 256, С. 117792 - 117792

Опубликована: Сен. 28, 2020

Язык: Английский

---

Iron-catalyzed stereoselective haloamidation of amide-tethered alkynes

Chemical Communications, Год журнала: 2021, Номер 57(35), С. 4259 - 4262

Опубликована: Янв. 1, 2021

In this work, by usingN-methoxybenzamides as efficient acyl nitrene precursors, an iron-catalyzed nitrene/alkyne metalation-based chloramidation is reported for the synthesis of isoindol-5-ones.

Язык: Английский

---