Radical NHC Catalysis

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(19), P. 11984 - 11999

Published: Sept. 19, 2022

Radical/radical cross-coupling reactions represent an efficient and straightforward approach for the construction of chemical bonds accordingly have drawn increasing attention over past decades. In order to achieve synthetically useful transformations, a persistent radical should be coupled with transient in accordance effect (PRE). However, known radicals outnumber by far types free radicals, which limits widespread application PRE, until today. Thus, development between has been focus, meanwhile transition-metal catalysis successfully implemented artificially prolong lifetimes, allowing their utilization formal radical/radical cross-couplings. Complementary research field recently uncovered that organocatalytically generated NHC-derived ketyl are type catalytically radicals. NHC-catalyzed transformations aldehydes carboxylic acid derivatives enabled disclosure ever-increasing number interesting reactions, different from traditional ionic processes, offering otherwise inaccessible activation modes. These discoveries opened door NHC organocatalysis manipulation reactions. Due its obvious potential synthetic organic chemistry, it is timely provide perspective on this emerging field.

Language: Английский

---

Native Amides as Enabling Vehicles for Forging sp³–sp³ Architectures via Interrupted Deaminative Ni-Catalyzed Chain-Walking

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(7), P. 3869 - 3874

Published: Feb. 8, 2023

Herein, we disclose an interrupted deaminative Ni-catalyzed chain-walking strategy that forges sp3-sp3 architectures at remote, yet previously unfunctionalized, methylene sp3 C-H sites enabled by the presence of native amides. This protocol is characterized its mild conditions and wide scope, including challenging substrate combinations. Site-selectivity can be dictated a judicious choice ligand, thus offering opportunity to enable bond formations are otherwise inaccessible in conventional events.

Language: Английский

---

A review of frustrated Lewis pair enabled monoselective C–F bond activation

Chemical Science, Journal Year: 2024, Volume and Issue: 15(8), P. 2712 - 2724

Published: Jan. 1, 2024

Frustrated Lewis pair (FLP) bond activation chemistry has greatly developed over the last two decades since seminal report of metal-free reversible hydrogen activation. Recently, FLP systems have been utilized to allow monoselective C-F (at equivalent sites) in polyfluoroalkanes. The problem 'over-defluorination' functionalization polyfluoroalkanes (where multiple fluoro-positions are uncontrollably functionalized) a long-standing chemical fluorocarbon for 80 years. mediated is complementary other solutions address and offers several advantages unique opportunities. This perspective highlights some these opportunities places development into context wider effort overcome 'over-defluorination'.

Language: Английский

---

Recent advances in three-component radical acylative difunctionalization of unsaturated carbon–carbon bonds

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(18), P. 4488 - 4515

Published: Jan. 1, 2023

This review highlights the recent advances in radical acylated difunctionalization of unsaturated carbon–carbon bonds and focuses on mechanistic insights these transformations.

Language: Английский

---

Photoredox‐Catalyzed Generation of Tertiary Anions from Primary Amines via a Radical Polar Crossover

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(6)

Published: Jan. 8, 2024

Abstract A method for the generation of tertiary carbanions via a deaminative radical‐polar crossover is reported using redox active imines from α‐tertiary primary amines. variety benzylic amines and amino esters can be used in this approach, with latter engaging novel “aza‐Reformatsky” reaction. Electronic trends correlate stability resulting carbanion reaction efficiency. The anions trapped different electrophiles including aldehydes, ketones, imines, Michael acceptors, H 2 O/D O. Selective anion formation achieved presence another equivalent or more acidic C−H bond both an inter‐ intramolecular fashion. Mechanistic studies suggest intermediacy discrete intermediate.

Language: Английский

---

Isonitriles as Alkyl Radical Precursors in Visible Light Mediated Hydro‐ and Deuterodeamination Reactions**

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(7)

Published: Dec. 27, 2023

Herein, we report the use of isonitriles as alkyl radical precursors in light-mediated hydro- and deuterodeamination reactions. The reaction is scalable, shows broad functional group compatibility potential to be used late-stage functionalization. Importantly, method general for C

Language: Английский

---

Mechanochemical Synthesis of Trifluoromethyl Arenes: Nanocellulose-Supported Deaminative Trifluoromethylation of Aromatic Amines

ACS Sustainable Chemistry & Engineering, Journal Year: 2024, Volume and Issue: 12(24), P. 8980 - 8989

Published: June 6, 2024

A convenient one-pot procedure for the mechanochemical nanocellulose-supported synthesis of trifluoromethyl arenes has been developed through selective transformation an aromatic amino group into functionality using pyrylium tetrafluoroborate (Pyry-BF4) and trifluoromethyltrimethylsilane (TMSCF3) via in situ formation pyridinium salt intermediate under transition metal-free conditions. The nanocellulose acts here as a green reaction medium, does not occur without this additive. scope present protocol includes 28 excellent yields (ipso-)substitution (SNAr) with CF3 functionality. This method could have great significance pharmaceutical industries late-stage functionalization active ingredients (APIs)/drugs.

Language: Английский

---

Direct C(sp³)–H Acylation by Mechanistically Controlled Ni/Ir Photoredox Catalysis

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(16), P. 2170 - 2184

Published: July 28, 2023

ConspectusSynthetic chemists have consistently aimed to develop efficient methods for synthesizing ketones, which are essential building blocks in organic chemistry and play significant roles bioactive molecules. Recent efforts focused on using photoredox catalysis, enables previously inaccessible activation modes, synthesize ketones through the cross-coupling of an acyl electrophile simple C(sp3)-H bonds. Over past few years, we worked developing effective versatile approaches directly acylating activated hydrocarbons forge ketones.Initially, thioesters were explored as source achieve direct acylation ethers, but unexpected thioesterification reaction was observed instead. To gain insights into this reactivity, conducted optimization conditions, substrate scope evaluation, mechanistic studies. Drawing from our understanding Ni/Ir photocatalysis obtained study, subsequently developed a method hydrocarbons. The use less-reactive amides electrophiles found be critical suppressing undesired pathways. This seemingly counterintuitive reactivity carefully studied, revealing substrate-assisted mechanism suppressed oxidative addition leads early-stage nickel oxidation C-H activation.To address drawbacks method, primarily arose decarbonylative transmetallative side pathways, employed N-acyllutidiniums electrophile. prevented decomposition enabling α-chiral substrates with retention their stereochemistry, particularly those derived α-amino acids. methodology allowed us access diverse range homologues.Despite elegant utility Ni/photoredox catalysis new synthetic methodologies, precise behavior catalysts under redox conditions is incompletely understood. insight chemical reactions, used combination experimental computational methods. Our investigations revealed that devised adjustments nickel/photoredox can result differences outcomes, providing opportunities tailor reactions designed strategies. We believe continued study apply modulation will lead discovery additional transformations.

Language: Английский

---

Visible Light Induced Copper‐Catalyzed Enantioselective Deaminative Arylation of Amino Acid Derivatives Assisted by Phenol

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(51)

Published: Nov. 8, 2023

The exploration of value-added conversions naturally abundant amino acids has received considerable attention from the synthetic community. Compared with well-established asymmetric decarboxylative transformation, deaminative transformation still remains a formidable challenge, mainly due to lack effective strategies for C-N bond activation and potential incompatibility chiral catalysts. Here, we disclose photoinduced Cu-catalyzed coupling reaction arylboronic acids. This new protocol provides series significant phenylacetamides in generally good yields excellent stereoselectivity under mild green conditions (42-85 % yields, up 97 ee). Experimental investigations theoretical calculations were performed reveal crucial role additional phenols improving catalytic efficiency enantiocontrol.

Language: Английский

---

Deaminative radical reactions via relayed proton-coupled electron transfer

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(9), P. 2155 - 2164

Published: Jan. 1, 2023

The detailed mechanism of these kinds N-heterocyclic carbene-catalyzed deaminative radical reactions has been explored in theory for the first time.

Language: Английский

---