Recent advances in the chemistry and applications of N-heterocyclic carbenes

Nature Reviews Chemistry, Journal Year: 2021, Volume and Issue: 5(10), P. 711 - 725

Published: Sept. 3, 2021

Language: Английский

---

Recent advances in N-heterocyclic carbene-based radical catalysis

Chemical Science, Journal Year: 2020, Volume and Issue: 11(22), P. 5630 - 5636

Published: Jan. 1, 2020

This minireview examines the history and state-of-the-art of N-heterocyclic carbene-based radical catalysis.

Language: Английский

---

N‐Heterocyclic Carbene Organocatalysis: Activation Modes and Typical Reactive Intermediates

Chinese Journal of Chemistry, Journal Year: 2020, Volume and Issue: 38(10), P. 1167 - 1202

Published: May 10, 2020

N ‐Heterocyclic carbene (NHC) organocatalysis has been developed as an important approach in modern organic synthesis. Versatile activation modes within NHC have established with countless transformations being realized both efficient and selective fashion. We would like to provide overview on the key progresses achieved this field past two decades. Since numerous excellent reviews documented area, we will mainly focus scientific development of research based basic reaction typical intermediates.

Language: Английский

---

Cooperative NHC and Photoredox Catalysis for the Synthesis of β‐Trifluoromethylated Alkyl Aryl Ketones

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(45), P. 19956 - 19960

Published: July 23, 2020

Despite the great potential of radical chemistry in organic synthesis, N-heterocyclic carbene (NHC)-catalyzed reactions involving intermediates are not well explored. This communication reports three-component coupling aroyl fluorides, styrenes and Langlois reagent (CF3 SO2 Na) to give various β-trifluoromethylated alkyl aryl ketones with good functional group tolerance moderate high yields by cooperative photoredox/NHC catalysis. The alkene acyltrifluoromethylation proceeds via radical/radical cross ketyl radicals benzylic C-radicals. generated SET reduction situ formed acylazolium ions whereas derive from trifluoromethyl addition onto styrenes.

Language: Английский

---

Combined Photoredox and Carbene Catalysis for the Synthesis of Ketones from Carboxylic Acids**

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(23), P. 9143 - 9148

Published: March 2, 2020

Abstract As a key element in the construction of complex organic scaffolds, formation C−C bonds remains challenge field synthetic chemistry. Recent advancements single‐electron chemistry have enabled new methods for various bonds. Disclosed herein is development novel reduction acyl azoliums ketones from carboxylic acids. Facile azolium situ followed by radical–radical coupling was made possible merging N‐heterocyclic carbene (NHC) and photoredox catalysis. The utility this protocol synthesis showcased late‐stage functionalization variety pharmaceutical compounds. Preliminary investigations using chiral NHCs demonstrate that enantioselectivity can be achieved, showcasing advantages over alternative methodologies.

Language: Английский

---

Light opens a new window for N-heterocyclic carbene catalysis

Chemical Science, Journal Year: 2020, Volume and Issue: 11(39), P. 10605 - 10613

Published: Jan. 1, 2020

N-Heterocyclic carbenes (NHCs) are efficient Lewis basic catalysts for the umpolung of various polarized unsaturated compounds usually including aldehydes, imines, acyl chlorides and activated esters. NHC catalysis involving electron pair transfer steps has been extensively studied; however, through single-electron (SET) processes, despite having potential to achieve chemical transformations inert bonds using green reagents, long a challenging task in organic synthesis. In parallel, visible-light-induced photocatalysis photoexcitation have established as powerful tools facilitate sustainable synthesis, they enable generation reactive radical intermediates under extremely mild conditions. Recently, number elegant visible-light-induced, NHC-catalyzed were developed accessing valuable compounds. As result, this minireview will highlight recent advances field.

Language: Английский

---

Direct α-Acylation of Alkenes via N-Heterocyclic Carbene, Sulfinate, and Photoredox Cooperative Triple Catalysis

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(13), P. 4903 - 4909

Published: March 24, 2021

N-Heterocyclic carbene (NHC) catalysis has emerged as a versatile tool in modern synthetic chemistry. Further increasing the complexity, several processes have been introduced that proceed via dual catalysis, where NHC organocatalyst operates concert with second catalytic moiety, significantly enlarging reaction scope. In biological transformations, multiple is generally used to access complex natural products. Guided by strategy, triple studied recently, three different modes are merged single process. this Communication, direct α-C–H acylation of various alkenes aroyl fluorides using NHC, sulfinate, and photoredox cooperative reported. The method allows preparation α-substituted vinyl ketones moderate high yields excellent functional group tolerance. Mechanistic studies reveal these cascades through sequential radical addition/coupling/elimination contrast known operate two sets interwoven cycles, process, all cycles interwoven.

Language: Английский

---

Aryl radical-mediated N-heterocyclic carbene catalysis

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

Published: June 22, 2021

Abstract There have been significant advancements in radical reactions using organocatalysts modern organic synthesis. Recently, NHC-catalyzed initiated by single electron transfer processes actively studied. However, the reported examples limited to catalysis mediated alkyl radicals. In this article, NHC organocatalysis aryl radicals has achieved. The enolate form of Breslow intermediate derived from an aldehyde and thiazolium-type presence a base undergoes iodide, providing radical. catalytically generated could be exploited as arylating reagent for relay-type arylacylation styrenes hydrogen atom abstraction α-amino C(sp 3 )–H acylation secondary amides.

Language: Английский

---

Cooperative NHC/Photoredox Catalyzed Ring‐Opening of Aryl Cyclopropanes to 1‐Aroyloxylated‐3‐Acylated Alkanes

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(48), P. 25252 - 25257

Published: Sept. 28, 2021

Cyclopropanes are an important class of building blocks in organic synthesis. Herein, a ring-opening/arylcarboxylation/acylation cascade reaction for the 1,3-difunctionalization aryl cyclopropanes enabled by cooperative NHC and organophotoredox catalysis is reported. The works on monosubstituted that contrast to heavily investigated donor-acceptor more challenging be difunctionalized. key step radical/radical cross coupling benzylic radical generated photoredox cycle with ketyl from cycle. transformation features metal-free conditions tolerates diverse range functionalities.

Language: Английский

---

Single-electron carbene catalysis in redox processes

Trends in Chemistry, Journal Year: 2022, Volume and Issue: 4(4), P. 277 - 290

Published: Feb. 11, 2022

Language: Английский

---