An overview on generation and general properties of N-heterocyclic carbenes: Applications of 1,2,4-triazolium carbenes as metal free organocatalysts DOI Creative Commons
Raphael Silva Moratório de Moraes, Maria Tereza Miranda Martins, Gabriel Tavares de Almeida Pinto

et al.

Arabian Journal of Chemistry, Journal Year: 2023, Volume and Issue: 17(2), P. 105527 - 105527

Published: Dec. 16, 2023

N-Heterocyclic carbenes (NHCs) have been widely explored in the areas of catalysis, organometallic and medicinal chemistry. In particular, NHCs catalyze formation C-C C-heteroatom bounds with high regioselectivity stereoselectivity through umpolung non-umpolung processes for unconventional access to create a vast scope heterocycle molecules, including β-lactones, tetrahydroquinolines pyrroloquinoles. Here we summarized generation general properties NHC important NHC-catalyzed reactions, which typically involve species such as Breslow intermediates, homoenolates, enolates α, β-unsaturated acyl azoliums, among others. Examples aerobic oxidative/oxygenative carbene specifically highlighting reactions involving oxygen strategies employed activation NHC-catalytic are discussed detail. The catalytic use has one most powerful tools chemist's arsenal, applications commercially protocols. Given this context, relevance N-heterocyclic chemistry is described review.

Language: Английский

Oxidative N‐Heterocyclic Carbene Catalysis DOI Creative Commons
Carmela De Risi, Arianna Brandolese, Graziano Di Carmine

et al.

Chemistry - A European Journal, Journal Year: 2022, Volume and Issue: 29(4)

Published: Oct. 7, 2022

N-Heterocyclic carbene (NHC) catalysis is a by now consolidated organocatalytic platform for number of synthetic (asymmetric) transformations via diverse reaction modes/intermediates. In addition to the typical umpolung processes involving acyl anion/homoenolate equivalent species, implementation protocols under oxidative conditions greatly expands possibilities this methodology. Oxidative NHC-catalysis allows and oxygenative through specific manipulations Breslow-type species depending upon oxidant used (external or O

Language: Английский

Citations

39
1H-1,2,3-Triazol-5-ylidenes as Catalytic Organic Single-Electron Reductants DOI
Mehdi Abdellaoui, Kai Oppel, Adam Vianna

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(5), P. 2933 - 2938

Published: Jan. 22, 2024

Most of the known single-electron reductants are either metal based reagents, used in a stoichiometric amount, or combination an organic species and photocatalyst. Here we report that 1

Language: Английский

Citations

11
Organocatalytic Transformations from Sulfur Ylides DOI Open Access
Marcio Hayashi, Antonio C. B. Burtoloso

Catalysts, Journal Year: 2023, Volume and Issue: 13(4), P. 689 - 689

Published: March 31, 2023

Sulfur ylides are an important class of organic compounds due to their ability perform many different transformations that can give diverse and interesting products with a high degree complexity. Although metal-catalyzed frequent in this compounds, organocatalyzed remain scarce. From initial works, review aims show from sulfur ylides, involving cyclopropanation formal N–H, S–H, C–H insertion reactions, including enantioselective versions. The proposed mechanisms the modes activation these organocatalysts will be covered. Furthermore, advances area potential challenges circumvented near future also discussed.

Language: Английский

Citations

13
How To Enhance the Efficiency of Breslow Intermediates for SET Catalysis DOI
Florian F. Mulks, Mohand Melaïmi, Xiaoyu Yan

et al.

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(4), P. 2535 - 2542

Published: Jan. 31, 2023

Oxidative carbene organocatalysis, which proceeds via single electron transfer (SET) pathways, has been limited by the moderately reducing properties of deprotonated Breslow intermediates BI-s derived from thiazol-2-ylidene 1 and 1,2,4-triazolylidene 2. Using computational methods, we assess redox potentials based on ten different types known stable carbenes report our findings concerning key parameters influencing steps catalytic cycle. From calculated values first oxidation potential to 10, it appears that, apart diamidocarbene 7, all others are more than We observed that while power significantly decreases with increasing solvent polarity, oxidant can increase at a greater rate, thus facilitating reaction. The cation, associated base, also plays an important role when nonpolar is used; large weakly coordinating cations such as Cs+ beneficial. radical-radical coupling step probably most challenging due both electronic steric constraints. Based results, predict mesoionic 3 abnormal NHC 4 promising candidates for oxidative organocatalysis.

Language: Английский

Citations

12
Photo‐Promoted Nitrogen‐Centered Radical Mediated Intermolecular Aminative Carbonylation of Tertiary Allyl Alcohols to Access β‐Amino Ketones through (Hetero)Aryl Migration DOI Creative Commons

Ming Hou,

Yuanrui Wang,

Hefei Yang

et al.

ChemistryEurope, Journal Year: 2025, Volume and Issue: unknown

Published: March 12, 2025

Abstract Carbon monoxide, as a crucial C1 synthon, has been widely used in the difunctionalization of alkenes. Additionally, nitrogen‐centered radicals (NCRs) are also effective intermediates for constructing C−N bonds. Herein, radical‐mediated aminative carbonylation strategy producing β ‐amino ketones from tertiary allyl alcohols disclosed. Good yields with different functional groups were generated effectively under light irradiation.

Language: Английский

Citations

0
Recent Update on Catalytic Activity of N-Heterocyclic Carbene Supported on Graphene Nanosheets: A Mini Review DOI

Raed Muslim Mhaibes,

Abdul Amir H. Kadhum, H Al-Salman

et al.

Journal of Organometallic Chemistry, Journal Year: 2025, Volume and Issue: unknown, P. 123660 - 123660

Published: April 1, 2025

Language: Английский

Citations

0
Plumbylenes based on redox-active ligands: Synthesis, optoelectronic properties and electrochemical behavior DOI

Sofya A. Fedoseeva,

Pavel G. Shangin,

Victoriya A. Balycheva

et al.

Inorganica Chimica Acta, Journal Year: 2025, Volume and Issue: unknown, P. 122724 - 122724

Published: April 1, 2025

Language: Английский

Citations

0
Enantioselective Synthesis of Dihydrothiopyranones via NHC-Catalyzed [3 + 3] Annulation of 2-Bromoenals with β-Oxodithioesters DOI

Shilpa Barik,

Sayan Shee, Rajesh G. Gonnade

et al.

Organic Letters, Journal Year: 2022, Volume and Issue: 24(48), P. 8848 - 8853

Published: Nov. 28, 2022

The N-heterocyclic carbene (NHC)-organocatalyzed [3 + 3] annulation of 2-bromoenals with β-oxodithioesters resulting in the enantioselective synthesis dihydrothiopyranones is presented. chiral α,β-unsaturated acylazoliums generated from and carbenes underwent smooth interception sulfur nucleophiles to furnish heterocycles satisfactory yields/selectivity. regioselective formation over competing dihydropyranones noteworthy.

Language: Английский

Citations

16
N‐Heterocyclic Carbene‐Catalyzed Activation of 3‐Membered Rings: Cyclopropanes, Epoxides, Azirines and Aziridines DOI
Xiaoqun Yang, Yi Zhang, Tingting Li

et al.

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(11), P. 1756 - 1769

Published: April 26, 2023

Abstract The activations of carbonyl compounds bearing cyclopropyl, epoxyl, azirine and aziridinyl groups by N‐heterocyclic carbene (NHC) organic catalysts are reviewed. reactions introduced discussed from 3 aspects according to the activation modes involved in these transformations. A brief summary on achievements remaining challenges NHC‐catalyzed cyclopropanes their analogues is given at end this minireview. Our own perspectives future development within highly active research field also provided.

Language: Английский

Citations

9
Shaping Chirality via Stereoselective, Organocatalytic [4+2] Cycloadditions involving Heterocyclic ortho‐Quinodimethanes DOI
Enrico Marcantonio, Claudio Curti

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(20)

Published: Jan. 18, 2024

Abstract Polycyclic compounds bearing a complex heterocyclic core such as an aromatic heterocycle “fused” with one or more functionalized rings, are widespread leading molecules in the domain of synthetic organic chemistry and pharmaceuticals. Although many methodologies have been devised to access achiral, fused heteroaromatic scaffolds, related chiral variants adorned out‐of‐cycle stereogenic elements, equally efficient strategies afford heterocycles featuring in‐cycle stereocenters, exist lesser extent presently represent growing field investigation. The mild, organocatalytic generation elusive ortho ‐quinodimethane intermediates ( o QDMs), derived from suitable carbonyl‐ carbonyl‐like pronucleophiles has recently proved successful synthesis peculiar architectures via stereoselective [4+2] cycloadditions. This review provides overview most important advances attained this over last decade.

Language: Английский

Citations

3